So, is your question actually "Who was the most influential band of the seventies?" 'Cos if so, you might as well throw Roxy Music in the running, and Sabbath, and... you get the point.
Frankie, the "Beatles of the '70s" is a dumb question for the same reason it's dumb to ask who was the Elivs of the '90s. It's an anachronism. There's nothing comparable, and so you're getting these answers that pick up on one aspect of The Beatles -- their popularity, their influence, the quality of their music, their record sales -- but not the others; and they ignore how radically The Beatles affected the world at large, not just other bands. The Beatles phenomenon literally changed the world in a way that's hard to imagine any band doing before or after. No one has. They also had the strongest seven-year run of any band that ever existed, created timeless music that cuts across every conceivable boundary -- genre, class, race... ABBA, Roxy Music, and Zeppelin are all partially correct, but what do you want? Did you start this thread just to make the dubious point that The Ramones are The Beatles of the seventies? It's an indefensible position, but you've made your point, okay, we get it, you love The Ramones. Awesome. How novel!