That's crazy. I've seen some pretty blatant attempts of making the opening band sound 'less' than the feature band - so petty/juvenile. Bill Graham did it right. He presented top-level bands of different genre's of modern music (Grateful Dead w/Miles Davis!) and educated listeners to a broad spectrum of contemporary music. He had it right - music is the key, and diversity leads to the broader comprehension/understanding. I leaned from his informed tact - music should not be a competition - it is a shared experience.
The "lessor" opening act BS is so old... I much prefer an evening where both bands are engaging.
Alex Cooley used to do that. Of course, in the deep south, it didn't always work. I forget who the opener was, but it was a mostly (all?) black world music band, and the worst of the Who fans booed them off the stage multiple times before they gave up. It was infuriating. Cooley (and, IIRC, Daltry) would get the crowd calmed down, and just a few minutes into the next song, ugly pandemonium.

