Its not really the cost thats the problem.
The 2 problems i see are that the technical overhead to start a instance is too heigh. And that peertube is majorly unprofitable.
Technical overhead can be solved with a service provider creating a single click to run service like moat of the Minecraft server hosts. Possibly even with a profit shair for zero cost startup etc.
The unprofitability is a harder problem to solve tho.