I couldn't care less about whether or not its commercial or was commercial... hair metal is damn good
Most of it's only a small step away from the true heavy metal of the '80s anyway and the only real differences are in the vocals (and not always there even), the attitude and the lyrical content. It's just got more of a rock & roll edge, but then so do heaps of true metal bands like Manowar, Scorpions, Accept, W.A.S.P., etc.
You can't really compare it to alternative/grunge/industrial etc. as far as both being the commercial types of metal. Firstly, hair metal is metal and the others aren't lol. And secondly, grunge is the exact opposite to metal really (completely against the whole leather, hair, guitar solos, big drums, high speed, etc) and is what killed it in the mainstream. All the alternative rock that's come out since then is a result of the grunge movement.
It's weird because the reason I think all that stuff was called "alternative" was because it was alternative to what most hard rock was at the time (the whole larger than life rock & roll thing), and now the true heavy metal and rock & roll has become the alternative to the alternative.