What’s less sustainable is centralized web. You must know that since you work for Amazon, right?
When PopcornTime was still a thing you could watch adfree any movie you’d like even in 4K because resources were shared through peer to peer.
Now, YouTube gets up to 12$ RPM, content creators get maybe 40% of that. With 2 prerolls and 2 midrolls + banners they get plenty enough money to make things work. Google has the most aggressive VASTs of the market. They are everywhere, called multiple times per pages.
Spare us your tears.
Besides, no significant competition? Is that a joke?