The hole I see in this idea is that we could have all of the benefits of Youbute, without "YouTube". All of the benefits of these services can exist without the predatory privacy invasive behaviour.
If you started your own site there's absolutely no way you could be profitable competing on both hosting costs and payout to creators.
I broadly agree that creators hugely benefit from these platforms, but that really doesn't seem to be what they're optimizing on imho. And you basically admitted they're a monopoly with that final statement.
Having a low cost infrastructure for video streaming and good advertising deals is not a monopoly, it's an investment.