...remember that quite a few potential applicants decide to not apply each year too due to the first few hurdles too (e.g. getting work experience, a decent mark in the UKCAT and etc). =P
Anyway, I don't think the competitions between medicine and most other courses are comparable - like many others have mentioned, medicine requires essentially a very different and selective procedure whilst other courses don't really (a test/interview to determine your competence/aptitude at the most).
Most courses basically just purely assess your academic ability or practical skills (e.g. artistic skills for art) to do well in the subject (e.g. see if you've done suitable subjects, got decent grades/predictions etc). Whereas for medicine, you're assessed not only on academic excellence, but also personal qualities, and various skills. The vast majority of applicants are more than capable and have demonstrated these various criteria well, so they're, instead, assessed against each other in a fierce competition for the places.
Just some examples to illustrate what I mean:
---a lot of competitions nowadays are extremely fierce (with 1000s of competitors facing each other off for like 5 winning places or something). The competition ratio sounds crazy but for a lot of them, only like 10% of the entries are really seriously considered by the judges because the vast majority of entries are just not up to the technical/professional standards they're looking for.
---It's a frequent thing to see academically excellent and talented non-medicine candidates getting all 5 offers from their chosen universities, whereas similar ones applying for medicine getting none. I came across a few people who have some of the most impressive academic history going onto to receive PhD/masters offers from top institutions, but failing to secure even just one offer at a medical school. Quite a few medicine applicants who have be unsuccessful in the past have decide to follow alternative career routes and many of them received offers from Oxbridge and the like too.