This is a bit random is it not? Oasis, tool, spice girls and soad.
Anyway.. Gilly did sum it up best in one line.
At the time Oasis had a great booster in that Britpop was the new thing it had been coming since the Happy Mondays / Stone Roses era. Oasis along with the help of Blur, NME, Ocean Colour Scene and just about any UK band with a record deal (excluding Pitchshifter) gained benefit, it was a fashion, exactly like punk and mods in the 70's early 80's.
...very few bands past or present as good as Oasis at what they do.
Oasis jumped into the middle of a upward spiral and came out top, quite possibly because they had good management/marketing. Their supremacy came about with the Blur spat, at that point that point they were given the crown, the interest died even with the band members, later they do nothing more than some TV interviews, (yeah, I do know they are mixing the new album this week).
That's what happened, they were lucky, the music business champions one band/artist as figureheads of a genre in that case it was Oasis.
They did well out of it.
Last year it was Amy Winehouse, this year probably Kate Nash.
I agree with the other person you spoke with.