I don't get this talk of comparing blues to progressive rock.
Jazz, as an art form provides more inspiration, in my informed opinion, for 90% of progressive rock bands.
I see Jazz Fusion inspired rock more as a progression from late Miles Davis than any snobbish racism aimed at blues and blues fusion groups, such as Led Zeppelin.
You only have to look at The Mahavishnu Orchestra for proof that Jazz influences "progressive" music.
Also, check out these Swedish prog rock bands from the 90s, they take inspiration from bands like Yes and King Crimson.
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Yeah the names are similar, maybe because the bands are similar.