@BrambleBearSnoring another way to think of this is to move people, and the information will sort itself out. Tech is all well and good but frequently deployed to solve the wrong problem.

Think of your favourite craft and the influential people on YouTube who share their skills in that craft. Maybe they watch each other's content. Maybe they help each other find an audience. Maybe they collaborate. Maybe they have a core bunch of mutual fans. Maybe some of them are already archiving. That's a community.

We need to come up with reasons to move those communities and present a case to them as a unified collective. Actual alliances are harder than the natural alliances people find themselves in having joined platforms due to the network effect, but those natural alliances are relatively fickle.

Once the community exists and is organised it's much easier to evaluate and implement tech for the community rather than asking individuals in a nascent community to move to something that isn't tailored for them personally or collectively. As it stands it tends to be the case that individual influencers on YouTube take on both the risk and reward of leading some community efforts.

Once the community moves the information will follow. Rinse and repeat for every human endeavour.