I gotta say that I'd have loved to have seen them hammering out raw rock and roll as teenagers (or youths at any rate) hopped up to the max on pharmaceutical speed for ten or eleven hours at a time in a stinking underground bar full of prostitutes and gangsters.
I loved them as a child, went off them as a teen, returned to them in my late 20s and now have more love for them and awe at what they did than ever before. People used to say of Michelangelo, in fact I think he may have said it himself, that what he was doing as a sculptor was releasing something which was already inside a piece of rock. It was there already and he was a channel for it. I feel almost the same about the Beatles, that they were writing melodies with such popular appeal that they were releasing something which existed inside us anyway.
I dunno how good they'd have been live towards the end, though, I get pissed off with people talking near me during gigs, never mind 75% of the audience screaming at the top of their lungs from start to finish.