You're being dumb. No one has ever said that Sabbath came out of nowhere and created metal and were never influenced by anything. Of course they were influenced by a lot of the bands you mentioned, and a lot of blues and blues rock. Hell, they began as a fucking blues rock band before becoming what their s/t defined them as: the first fucking metal band. Nothing before Sabbath was as heavy, as foreboding, as sinister, as powerful, etc. Sabbath singlehandedly made "metal" an actual classifiable sound (which has, of course, been extrapolated in the present). Yes, there were bands before Sabbath that were as heavy, bands that were creepy and dark, bands that played with downtuned sludgy thick guitars. But none of them put it together as well as those first notes of that goddamn album.