Was Hendrix really a "rock" guitar player? He could play legit r&b and blues, too. "Ice Cream Man" sounds like a rock guy playing blues, "Red House" or "Hear My Train A Coming" sound like a blues player.
Regardless, the one thing in common with so many greats is they have a definitive style. You hear a lick or sound and you know it's them. They are all innovators, albeit some more so than others.