Before the Beatles, bands didn’t play that large of venues. However, I’d be hardpressed to say that earlier acts/performers weren’t as talented as Taylor Swift, etc.
The “big event” rally show is something I don’t connect with. If you go to them with your friends, half of your memories are the people you went with that night. However, if you go alone the shows are a remote experience.
The Beatles and then Woodstock changed the music business. Bill Graham wanted bigger shows with one performance a night instead of having to turn a room and sell tickets for two performances (and pay the band more).
If a band could “only” sell 3,000 tickets, they weren’t considered as worthy...