Clapton hardly discovered SRV. By 1990 I had probably seen SRV play 5 times and he was plenty big by then.
Clapton is technically a very proficient player - but so are thousands of other guitar players all over the world. Where he falls short is he lacks originality and has no style of his own. What Clapton had is that he is a "media darling" - he fits the mold of what the media thinks an aging rock guitarist should be. He photographs well. Hendrix was about 5 million times better.
But Joe Walsh? Why he's so far better than anyone else it can't even be measured!!!!! LOL.....