a) you know this for fact? or you're saying this "would have happened anyways" as a hind-sight evaluation using revisionism as your guide to say "it happened in our history so of course it would have happened that way even without the beatles"? i know the answer to this, but judging from your post, i doubt that you do.
b) the beatles made such future bands much more palatable for mainstream audiences, ensuring the ability for such bands to enjoy the prominence they were able to achieve. the beatles dragged their audiences from bubblegum pop through an evolution of music which would not have been possible before.
here's a thought experiment: ask yourself would Sgt. Pepper have been commercially successful has it been released in 1962, rather than 1967? the answer is no. there was no precedent in 1962 for that kind of creativity or that diversion from what was then mainstream pop music taste. could it have existed? absolutely. if an unknown band has released "Pepper" in 1962, it would have reached a devoted audience that would likely have numbered in the dozens and never amounted to more than an visionary but odd-for-its-time album.
as an aside: the question of "would it have existed in 1962?" is no. no band at that time could have convinced a record label to invest in all of the resources used by the beatles during Pepper, except for a band who was the #1 world wide draw and could guarantee a return on the label's investment. maybe Elvis could have gotten it made, but the odds of Elvis creating Pepper
ex nihilo are astronomically low.
as the beatles evolved into more and more challenging music, they lead their fans into accepting a much richer and more diverse breadth of bands and musical styles. would the Doors have even formed? perhaps, but perhaps not. would their style be the same as what actually happened? i really doubt it. if it was, i don't believe that the audience for it would have been as large.
it also didn't hurt that endorsements from the beatles were tremendously helpful to advance these musicians. from wikipedia's article on Jimi hendrix:
http://en.wikipedia.org/wiki/The_Beatles%27_influence_on_popular_culture#Jimi_Hendrix
Quote:
McCartney had publicly endorsed Hendrix for months, before Hendrix broke into the UK music scene.
hmmm, i wonder if there was no beatles, and thus no value in Paul McCartney 's opinion, would Hendrix have had the same reception in the UK? Possible, but having one of the most famous people in the world opening doors for you makes life an awful lot easier.