I think the truth of the matter is closer to 1neeto than to you, Blob.
Nirvana's place in music history is assured. People take them seriously and respect them, even if they don't like them all that much.
No one now gives much credit to the hair metal bands (even if they should), except for the statistical outliers like you, Coz, and a few others. Sure, there is a dedicated audience, but it is relatively small.
There was some great music made by hair metal bands (I like a lot of it), but it was typical 80's, as with everything else that decade: style over substance, image is everything. I feel like the really great songs that were produced were almost by accident.
Just my two cents.