I didn't know Air Supply ever purported to be metal, so not them. Probably "Quiet Riot." It seems their only intention was to pop out a couple top-40's and quit trying. Def Leppard is a strong second. I like their music, but they were "riding the fence" when it came to going full metal, and never picked a side. Or I guess they did, actually?
Quiet Riot?
They didn't even "pop out" any top 40 crap. They borrowed "their" music.
Come on feel the noise...
And,
Mama we're all crazy now...
Were both originally performed and recorded by a band named
Slade
Quiet Riot's only "talent", was doing cover tunes.
....
Worst band ever?
It's a tie, between 'Hanson'
and the Beatles.