Youtube regularly spits on its content creators and they come crawling back for more, that's how few alternatives Youtube has out there. Youtube is not currently at risk of death. Reddit might hemorrhage more users come July, but it hasn't died and won't die anytime soon, either.
I don't think anything will ever replace YouTube. Did you ever wonder why there aren't many good alternatives?
It's because video streaming websites are very expensive and usually run at a loss. The storage and bandwidth to support all these users constantly uploading and watching videos is really high. It's why the Twitch competitor Mixer shut down a few years ago, it was bleeding money.
I use an adblocker and hate ads as much as the next person but imo prople do take these video services for granted. They need ads to survive and I can't imagine a world where I'd need to pay a subscription to use them.
I have to wonder how effective PeerTube might be in lessening the bandwidth costs at scale. So far the PeerTube instances I've seen have had so few users that I rarely see my computer uploading to other users or other users uploading to me.
The only problem is YouTube has a way to monetize their videos, attracting creators who work to make money on the content. PeerTube doesn’t have that yet.
Handling ads and payments is a whole other issue that federated platforms haven't even begun to tackle yet. Crypto might be a way forward but it's messy enough that it might turn some people off.
It's in the same boat as Reddit is where it has gained a lot of goodwill by providing free content hosting for pretty much anyone, but because they've done that for so long it's seen as having little value, so attempts to generate value from it are resented.
I'm a lot more sympathetic to YouTube than I am to Reddit though, to put it bluntly.