I'm not sure you'd say SRV was actually in Double Trouble or whether they were purely backup to him...almost a separate but congruent entity. I know those 2 guys played together backing other people before, and under the same name if I'm not mistaken. But I'd say that's just band name semantics, and those 3 were tight like brothers after starting out. So yeah, it was Stevie who fronted them and "made" it.

This is an interesting concept though...as some of the usual guitar heroes come to mind, it's worth wondering how much is due to the rest of the band. Alex Lifeson for instance: awesome guitarist, but his bandmates are equally virtuosos of their respective instruments. Or how much of Led Zeppelin was Page's riffs versus the thunderous Bonham and multi-talented John Paul Jones?
Unfortunately sometimes this question is answered for us. Axle Rose's touring version of G'n'R...yeah right. But as great as Gilmour is, Floyd's not quite the same without Waters.

So being that it's harder to name guitarists who made the band, illustrates the importance of chemistry with everyone in the band. Many a poor solo career testifies to this.