I recall shooting a friend's AR-15 in the 1970's and being very impressed by the ergonomics and sights, as in 'Wow! that's really easy to shoot! Sure looks weird, though...'. And IIRC it was really expensive relative to a Remington 700 or Marlin 336 or whatever (but I may be wrong, corrections welcome).
My sense is that they would still be popular today with or without an AWB. The cost has come down, you can do the modular thing, you can have the same lower with Geissele trigger for multiple uppers, a barrel swap doesn't need a trip to the gunsmith, yadda, yadda, yadda. Cars don't have naugahyde seats anymore. As people gradually got used to them, and folks came out of the military familiar with them, I think they were going to take over regardless of the politics.