Everyone pitches in

Aaaaaand that idea is dead in the water.

Something like Youtube requires way more bandwidth, storage and processing power per user than something like reddit. Which is why they're trying to make more money.

Lemmy works because it doesn't take all that much in resources to run an instance, and having single digit percentage of your users chipping in can be enough. A decentralized YouTube would not work quite the same, and you'd have a hard time keeping the creators paid too.