In response to mrmojo1120's comment:
In response to devildavid's comment:
I need some examples of what is considered mainstream today. I think some of our opinions are a product of our age and our memory of the past. I remember a lot of crap from the seventies that was not the greatest achievement of high art. I have a Super Hits of the Seventies collection full of such evidence. Afternoon Delight; Convoy; The Bertha Butt Boogie; Don't Pull Your Love; Brand New Key; Daddy Don't You Walk So Fast; Billy Don't Be a Hero; Kung Fu Fighting; Chevy Van; Feelings; Don't Give Up On Us; to name a few. But don't get me wrong, I enjoy a lot of that low art pop pap. I think the Seventies mainstream could give today's mainstream a run for it's money for disposable pop music.
I guess I disagree with the premise that only recently has mainstream taken on a derogatory connotation. I think it always had that connotation among discriminating music fans and music performers too. But the mainstream audience has always looked favorably on mainstream music and I don't think it is now any more widely accepted that mainstream means "garbage".
I'll bet "The night Chicago died" is on that 70's collection album too.
Bingo!