Both I think. There are always innovators in every cultural form, and there is a spectrum from the actual first movers/avant-garde through early adopters to forward-thinking mainstream popularisers to trend-followers and mass adoption; the Beatles were unusual in at least two ways:

1. They had feet in avant-garde and early adopter camps.

2. They had a popular impact that has arguably never been matched (I include eg. Sinatra, Elvis, MJ and Madonna etc) which lifted the normal "populariser" contribution to your cultural shift.

So there are other huge bands or artists in the progressive, influential respect, people like eg. James Brown, Nirvana, Kraftwerk, NWA etc etc and lots of influential but not commercially successful or mainstream acts.

The Beatles though were arguably more progressive than even those, and on a completely different level in terms of cultural reach. That's what makes them special.

Btw they're not really a band I listen to much, in case there are any "you're just a fanboy" suspicions motivating counters to this. :)