I seem to have missed the last thread, so I'm happy to come into this with a fresh pair of eyes.
First of all, nepotism does still happen in the legal industry. It happens in just about every industry. There are, however, two points to make.
The first is that in more recent times it has become much harder, if not impossible in many situations, for people to be directly offered jobs because of family connections. That's primarily because recruitment processes have become so much more refined. To give a pupillage process as an example, my set anonymises applications, has two (random) barristers from a pool of around ten to assess each one, and then a further check by different barristers for applications with large disparities. Should you then get an interview, you can again not guarantee which barristers will interview you, and decisions made by an interview panel are made by the panel and not individuals. The barristers in the pool are then rotated year to year. All that makes it basically impossible for anyone to be offered pupillage through nepotism. I'm not suggesting all recruitment processes are that robust, but most will have many more checks and balances than in years past which makes nepotism very difficult.
Second, clearly nepotism doesn't have to mean only being offered a job. Having connections generally (whether through parents or not) can make a difference earlier in the process when someone is developing their application, for example for work experience. Having connections may also mean that someone gets to know people in positions of influence, that they receive particular opportunities and so on. There is nothing necessarily untoward about that either. It can often happen quite naturally. If your father is a QC, for example, chances are you're going to learn quite a lot from him just by virtue of living in the same house as him and him being your father. If he's friends with other lawyers you may have met them socially just by virtue of that friendship. There's nothing inappropriate in any of that.
Which brings me to the present question. I have no idea about these individual firms and recruiting trends within them. I'm a barrister and not in London. But the basis of the assumption of nepotism seems particularly thin to me. In fact, saying it's thin is generous. I know law students and lawyers love to talk, but if you're reaching conclusions on the basis of "rumour has it" you need to stop and reflect on that. Yet the NQ reasoning doesn't even go that far. "No doubt his father knows" is the basis of that. Come on. That's just silly.
But of course you do ask whether you're missing something, so might I suggest you're missing this person's actual strength as a candidate? If he was a weak candidate I expect you would have mentioned that, because if he isn't it's desperately difficult to land on nepotism as the most likely reason for them being offered the TC and then NQ position. I'm going to give two more quick examples for you.
First, I missed out on a pupillage offer by the skin of my teeth just after finishing the Bar course. The guy who got it was on my Bar course and overtly wealthy. His father knew the Head of Chambers and the guy had arranged to go on a ski trip with some of the barristers even before he was offered pupillage. So naturally I comforted myself with the conclusion that he got the pupillage because of his connections, but the reality is that we really were of comparable strength as candidates, and it wasn't objectively unreasonable at all for them to pick him over me. With hindsight I completely acknowledge that.
Second, one of our more recent pupils not only had the benefit of a very senior judge as a father, but also got pupillage at our set, which happens to be the same set that their father practised at when he was at the Bar. "Surely," I hear you cry "their father must have influenced the decision to offer them pupillage!". I mean, it's obvious isn't it? I expect some of the person's friends on the Bar course might have thought the same thing. Except, he didn't. Not at all. I was on the interview panel for that person, and after his interview one of the barristers (turns out, very good friends with the judge) said that he wanted all of us to say what we thought first. We did, and we all thought the person was exceptional. One of only two candidates to get full marks from all of us. The barrister then said he knew the candidate and told us who they were (we all knew the judge). Not only had the judge not put in a good word, but he hadn't even told that barrister that his child was applying for pupillage with us. That candidate was offered pupillage, and the fact that their father was a judge and former member of chambers had, I promise you, not a single thing to do with it. They were the best candidate (along with the other person who got full marks, who was also offered pupillage). Which makes sense to some degree, because you're bound to pick up a thing or two when your father is a senior judge and former barrister, right? Which is the point I made above. But still, they got that pupillage entirely on merit, when I fully expect outside observers assumed nepotism.
The bottom line is that nepotism happens, but it is much rarer than most people think. It is also very easy to jump to nepotism as a conclusion when you have no actual evidence of anything inappropriate taking place, and I'm afraid the latter is far more common than the former, mainly because it is regularly not acknowledged that children of well positioned parents are, in fact, often very strong candidates in and of themselves, partly because of the influence that their parent(s) have had on them.