Nowadays, there are a lot more distractions. Musicians are too busy working on their social media game to actually work on their music game. And with nightclubs using canned music or one-man DJs, there's a lot less opportunity to perform live even if you want to. This is technological change which harms new music, and it more than cancels out the improvements which technology brings to music.
But yeah, the whole business today is a much different world from the music scene of the 50s/60s. :)
The "8-10 hours per night in hamburg" were intense, but they only did a few stints of a few months at a time there. I think Lewisohn added up after their first trip in '61, they had something like... 800 hours of stage time under their belt. It's a lot, certainly, but not the 10000 hour sort of thing people sometimes think. BUT... what's interesting is that there basically weren't any other rock bands at all with that amount of "stage time as a unit" either. It was a relatively new thing altogether, certainly in the UK...
George Martin was a great composer in his own right, and Geoff Emerick/Alan Parsons could bend the antiquated technology to their will. Then you have Paul who is a really good producer and John who is a great abstract thinker. So there is no single voice coming from a Beatles record.
Compared to today, where everyone switches producers every album (or on the same album), staying mostly in the same place with the same group of support people for... 7 years is relatively remarkable, and, I suspect allowed them all to grow together in various ways.
They set a standard which was followed/copied for decades - self-contained music group writing/performing their own material. And they were really good at it.
The one thing that didn't get copied from them in most cases was multiple singers. They didn't really have a 'front man'. They had a lot of harmony singing. These are keys missing from most of the bands that copied them over the years.
The voices worked well together, but were distinct enough, and the songs were distinct enough, that one could enjoy 'George' Beatles music without caring much for 'Paul' Beatles music (for example).
If you don't like Bono's voice, you're going to struggle with liking U2. If you don't like Stipe's voice, you'll have a hard time being an REM fan. Don't like Mick Jagger's voice? Tough luck on digging the Stones too much.
There was also enough variety to allow almost everyone to be able to find some Beatles track they love (or at least like).