Well, for one thing this phenomena was going on well before 91, the difference being that it is now amplified to the nth degre only because of entertainment being the new religion. People worship artists of all genres and denomination for a lack of spiritual pursuit. Even the most obscure artists get to have their own cult.
If you look closely at all the bands that recorded during the Elvis' fifties and the British Invasion that did not so much as register a blip on the radar it is amazing. Find the scrap-yard-second-hand record store in your town (there is always one, usually closes after a month of operation) and you will be able to find the most amazing amount of music that was forgotten before it ever was recorded.
The main difference that I see is that nowadays, marginality is more hip and it is way cooler for some kids to say that he likes obscure artist than the flavour of the month. And the Net has helped the avalability of such work.