Why does it need to compete with YouTube? Is it really a zerosum situation?
The value of such a thing has a lot to do with how many people use it and how much content there is. You need users to give incentive for people to upload content. And you need content to incentivize new users.
Tech diversity in itself is a value, even if the niche players never leave the niche for the most part. Diversity allows for adaptability in a changing environment/crisis.
I believe the mass social network epoche is about to end, as the advertisement/influence ecosystem is eating up its island's last trees. The dream of the global internet failed, for reasons we can't fix. ActivityPub is much better fitting a fragmented network.