I have 4PB, but my understanding is that I would fill that mirroring a single day of YouTube at reduced quality. The Internet Archive could surely handle mirroring older YouTube content with a large grant. But the upload rate plus video quality in recent years is definitely cost prohibitive to replicate.
The point I was trying to make is, data hoarders collectively archive a lot of data. They have interests and tend to mirror their interests from the sites. As a result, they can mirror a substantial amount of videos or knowledge from any gigantic site.
I'm aware that even a horde of data hoarders can't archive a drop in the YouTube ocean, but by archiving high-impact channels, they can backup both important and vast amounts of information.
