Are humanities / arts / social sciences degrees worthless apart from being a hobby

I think in this day and age of easily transmitted misinformation, strong comprehension and critical thinking skills around the things we read is more needed than ever, actually. It's not just about reading books, it's about how we consume information and how we interpret that information - of course STEM courses do require this skills too, but largely when you're reading a technical resource for a STEM course you can assume the contents to be true. A lot of humanities focused courses teach you how to draw your own conclusions about what is true or false based on a variety of sources. That is definitely a valuable skill, no matter how you swing it. If you think about the course content uncritically (that they are just reading books) it's easy to see why you would miss the value there, but it isn't the "reading books" that is the learning, it's the way those books are interpreted and critically read. (And it goes without saying, but nobody is reading Harry Potter at degree level.... I assumed that was obvious.)
I did an arts degree, in a subject most people would assume would be completely pointless - Game Art - but I learned how to use complex digital software for 3D modelling and game development, worked on creative projects, and have a successful career in the video game industry. You could argue my role comes under the Technology in STEM (I would agree) but the point stands that I still did what would be fairly unanimously considered to be an arts degree (I didn't write a dissertation, or sit any exams).
As for a lot of people that work in the arts, we work in entertainment - your world without art, music, film, tv or games - without archive and the ability to learn form history in the forms of galleries, libraries and museums, without fiction - that sounds like a worse place to live, for everyone, STEM graduates included.
Yes - it's a higher risk pathway, and arts and humanities students skew to be from more privileged backgrounds (when you don't have to worry about supporting yourself and your family, you can afford to take more risk in your career) I don't want to downplay that. But it being higher risk doesn't mean people don't have successful and impactful careers - plenty do. (In fact, i'm passionate about making creative careers more accessible to more people) I will give you the benefit of the doubt in assuming that it's the frustration at the privilege of being able to aspire to a higher risk career that made you write this.
From your post history it's clear you place a high value on AI - and while I think there's a place for AI as a tool to support people in their careers - I should be clear that I think it is most valuable as a tool to be used to aid and not as a replacement or substitute for a real person - else we risk recycling the same ideas that have already been thought up for the rest of human history, without ever creating something new, not to mention that AI is often less than perfect in it's outcomes, and can very convincingly misinform.

I didn't get to be in the Harry Potter films as an extra, despite reading music at Oxford whilst the films were being made. Should I ask for a refund?!!?!?!?!?!!?!? I didn't get the magical experience that I'd applied for

If you want to take things too literally so can I.
You graduated with a Music degree from Oxford but you are herding goats instead of being a bigger musical sensation than the Beatles (who had no degrees at all).

How do you know I'm not being a bigger musical sensation than The Beatles, whilst herding goats?

Arts / humanities / social sciences degrees are just taxpayer-funded 3-4 year luxury university experience where students do nothing that requires intelligence or logical inquisitive thought, nothing that could possibly benefit mankind, just reading books like Harry Potter and Shakespeare that they have already read before joining uni or learning some languages that are all about exposure and could have been learnt free of charge and more efficiently on Duolingo, and hallucinating the most pretentious, non-original thoughts (aka waffling).
These mickey mouse degrees have no objective standards, no rigorous train of thought other than what the student "feels like". Needless to say there is no real skill gained and the only skill required is "literacy" which isn't really a "skill" but a necessity / prerequisite nowadays. STEM students are usually required to possess even higher standards of literacy (than arts humanities and social sciences students, ironically) due to the stringent standards and precision of STEM subjects. This has always been true even long before AI and LLMs.
Oxford & Cambridge (Oxbridge) arts / humanities / social sciences degrees are even worse as taxpayers pay even more to fund their Harry Potter reading experience. The tutorial / supervision system is wasted on a bunch of Hogwarts Harry Potter wannabes who are there just for the "magical" experience.

How do you know I'm not being a bigger musical sensation than The Beatles, whilst herding goats?

I agree that there might be some subjective value in the arts / humanities / social sciences areas.

One of the gists of my argument is that whether degrees in those areas are worthless / anything more than a hobby. It is true that the world has seen some seriously talented artists and musicians (subjective opinion), but the most economically successful artists and musicians (think Beatles, etc.) actually did NOT study for an arts / humanities / social sciences degree.

I mentioned "Harry Potter" as a synonym for Mickey Mouse, English Literature, Shakespeare etc. The Harry Potter novels have nothing inherently different from, say, Shakespeare's plays, or indeed any other work of literature / pure fiction that is studied as part of, say, an English Literature degree.

I can easily argue that arts / humanities / social sciences are too subjective for students to develop critical thinking skills - they simply cherry pick sources that support their subjective opinions, thereby magnifying subjectivity.

Humanities have remained stagnant (dare I say deteriorated) throughout the ages, whilst AI capabilities are growing exponentially (since its "debut" in the last 2-3 years)

How do you know I'm not being a bigger musical sensation than The Beatles, whilst herding goats?

Erm cos objective industry statistics tell me that the Beatles are the best-selling musicians of all time? Subjectively you could be a bigger musical sensation than any musician the world has ever seen, with sold-out concerts and encores in your bathtub.

I was merely pointing out that being a huge music star is not automatically totally ncompatible with having or herding goats Not necessarily saying I'm bigger than The Beatles

You asked me how I knew you weren't "a bigger musical sensation than The Beatles, whilst herding goats". Logically if you definitely aren't "a bigger musical sensation than The Beatles" then you definitely aren't "a bigger musical sensation than The Beatles, whilst herding goats".
I didn't say they are incompatible concepts.

Let's reframe the topic to what skill does a DEGREE in arts / humanities / social sciences add to a student that he/she cannot already obtain simply by reading books in that subject without being enrolled in a degree programme.

A degree in arts / humanities / social sciences is nothing more (and potentially less) than a certificate saying somebody spent 3 years' worth of taxpayer money to read some novels.

I don't doubt that different works of fiction have different impacts - but since the topic is on DEGREES in art / humanities / social sciences, are you trying to say one must have a degree in art / humanities / social sciences in order to be a successful writer / artist? William Shakespeare already proves you wrong.

What impact does Harry Potter have on the society? It is basically a novel about a pseudo Oxbridge institution written by a non-Oxbridge outsider (JK Rowling studied at the University of Exeter, I bet the posh kids there wished they studied at Oxbridge). Harry Potter fans dress up as Hogwarts students. So what? None of that is comparable to, say, Sir Tim Berners-Lee's invention of the worldwide web internet.

Not to mention arts and humanities have a track record of inciting violence, I'm talking about Adolf Hitler and the upper echelons of Nazi Germany, and possibly religious fanatics throughout history.

I think it really is very telling how the OP claims a humanities degree involves no "rigorous train of thought" other than what they "feel like" while repeatedly posting threads which involve no rigorous train of thought other than what they feel like. Meanwhile the entire point of a humanities degree is to learn to develop nuanced and critically informed academic arguments.

This bizarre "STEM superiority complex" is really rotting the brains of kids today. Perhaps because...they didn't get enough training in the humanities and allied fields?

Also the fact the OP has to invoke Godwin's law within 6 hours of making the thread really underpins just how meaningless the thread is.

Yeah while it's easy to say I took the bait here, I think while this is likely dramaticised for engagement there is definitely some real genuine feelings in there from the OP about feeling better than everyone else and that "i'm studying a REAL subject unlike everyone else who's just messing around" - super toxic, super unnecessary. Generally just an unhelpful way of viewing other people, anyway - you'll get a lot further in life by respecting people regardless of their educational background than critiquing what/if they decided to study.

And yes absolutely, there's some wonderful irony in there about ability to critically consume information, lol.