I'm gonna disagree with you a bit here. It takes a broad brush to paint the entire commercial music industry as single heavy filler filled album creators. What of the truly great artists that transcend such labels? The Beatles
certainly weren't underground, yet I challenge you to name a filler filled album they released. Typecasting musicians as commercial/underground/alternative(to what) is pointless. Granted, unless you're an eleven year old girl, Britney Spears
album is gonna suck to you, but that eleven year old is also gonna tell me the incredible Ivan Boogaloo Joe Jones guitar solo
I'm listening to sucks. Britney's pretty obviously a commercial creation (sell out for all your worth girl). Ivan literally sold 2500 albums in the sixties, and has been brought back by rare groovers -- that's pretty far underground. There are two kinds of music, music I like and music I don't like. Play what you got, I'll classify for ya.
What I'm saying here (the long way round) is beware the popularity trap -- i.e. it sucks because everyone likes it. Some things sell a lot because they are good. Remember that the Beastie Boys had more in common with the Backstreet Boys when they broke out than with the highest pantheon of hip hop which they are know a part of. Eminem can rap his ass off better than all but a handful of MC's, and he's a "pop" music sensation. Does that make him less skillful on the mic?
Aw to heck with it... Judge artists individually. Don't shoot them because of their messenger.