I take a deep breath, remind myself that I have long legs, and do a big split right over the big pond! I can hardly imagine life without the music from BOTH sides of the Pond (and a few other places, too!).
Let's not forget that those early Brit bands were all inspired by American roots (by their own admissions); America is where Rock was born. Neither can we foget how the British bands took hold of that inspiration and made more of it, how they in turn re-inspired yet more American artists. I don't think either side would or could have produced what they did, without influence from the other side. At least, it's highly questionable whether the Brits would or could have evolved in the directions they did without American imported discs. Yet what they did with those influences was special, by any account. The Beatles, The Stones, The Who, Led Zeppelin --Rock just wouldn't be he same thing without such Juggernauts.
Fortunately, the rock era encompassed a time when not only recordings but also groups themselves could travel, too, and did so where the common language and cultural roots made bigger markets possible. The Beatles toured America. Hendrix went to Britain. There was a lively cross-pollination and many groups had hits in both markets. I see the two markets as inter-linked and inter-related.
Oh and I take it "America" includes Canada, too. What would rock be even with The Who, if it didn't also have The Guess Who?!