Well yeah ok, but they were pretty much pioneers of metal in general

While yes, obviously Kyuss's mega-riffs are a translation of Sabbath, they still made music that in their day and age was original, violent, and pretty much all over rock & roll.

...and Orange Goblin and Clutch and on and on...

I have altered the description because Kyuss was not THE band to popularize the sound; they were one of many. But honestly, how many people do you think have heard of the bands you've just mentioned (other than Sabbath)

Pioneers of playing stoner metal in the open desert.