I think in part because the early 90s Internet was before the majority of millennials were really heavily online. I’m an '88 millennial, and my childhood Internet was still early 2000s, mostly.

Stuff like IRCRizon and Limewire and Geocities and even Gaia Online over DSL, rather than BBSes over probably AOL dialup (I had that as a kid, but only as a very young kid, i.e. literal preteen.

Nyan cat and motivational poster memes are my golden age, not Usenet.