It would make a difference to some bands where that kind of validation (vs sales and revenue) is key.
That being said, I think it's inevitable that any field of endeavor with that much societal influence and that much money IS going to have some kind of recognition body. So, even if that particular Hall of Fame group failed, another would stand up. If so, they might stand up somewhere else, perhaps influencing (or responding to) evolution of rock in different places.
What if the Rock and Roll Hall of Fame ended up never happening (not just the museum, but the RARHOF Foundation in general)? Would there be a significant impact on music?