And I'm 30. I remember when that song came out.
My point is that "old school" is too all encompassing. So much so that it almost doesn't mean anything at all. Basically just that it hasn't been "hot" in the mainstream for 5+ years.

That kinda dichotomy just isn't useful for anything that's more than a decade old. And like you said, the generations in hip-hop move very fast making "old school" even more useless.