Swears had quite a good thesis about this, I think.
Edit: in response to those forum posts about how nobody will remember the 90s.
But doesn't this just push the question back one step... so it becomes "why not?"?
That is to say that
@swears may have fairly astutely spotted what didn't happen. And sure, quite possibly he was correct when he homed in on the following
"... no break like punk rock or acid house at the end of the 90s to really set the stage for a new style or attitude towards music and pop culture in general."
... as THE most clear and crucial sign that unlike previous decades the 90s never had a clearly marked ending that swept the slate clean and created a cultural space in which the next decade could happen.
So yeah, not only did he identify the sign, he was able to boil it down into one very easy to grasp sentence, in fact one very simple to grasp concept. Which is not to be sniffed at, it's not an easy thing to do, certainly I never saw K-Punk get close to achieving it in what was (or ought to have been) years of trying.
But...
But, but, but, buuuuut... hold on a minute there, now we know what didn't happen, are we any closer to knowing why it didn't happen? Do we know what to do in the future we so that we can make sure it doesn't not happen again? Can we fix it and get back on track by simply making sure every cultural period finishes at the right time and in the right way?
Or do we have to fix the ending of the 90s and create a parallel universe where culture is good and then go down that trouser leg of time paying vigilant attention to assuring every period is properly marked off by decade-closing palate-cleansing new genres of our own devising?
And how the fucketty fuck do we do that?