Personally, I don't consider it a valid point.
It only costs so much to share some data because of massive centralization by the likes of Google and ISPs, and can only be sustained because of t sustained because these "subsidies" from large players. It's not technically hard to distribute some videos efficiently, but the market is less than 1/10000.
Maybe in 5 years it will be near impossible to host a web site without being DDOS-ed, but I won't praise Cloudflare for their now-possibly-not-free service, I will blame them along side ISPs.
These were the prices before YouTube really became big and were still the prices after they became big.
I've worked in video streamin industry in years and I haven't seen YouTube be the fault of the high costs. It mostly comes from the fact that videos are large, they need a lot of CPU power to convert and need a lot of bandwidth to transmit to clients.
As for CPU, storage - I don't think 10+ different formats at extreme compression are a hard requirement.
Youtube ads are good, as people will have incentive to use peertube and similar.
¹ You need some seeds, but they don't need Tbps pipes.
And a willingness to steal...
It's illegal and if everyone did it, movies would not exist.
If everyone that wouldn't have paid pirates a movie then nothing bad happens and people enjoy things.
Arguing one of those facts while ignoring the other one is a mark of a bad argument.
You can't just assume that people that don't use your service would be paying customers if a specific alternative wasn't there.
It's easier to demand YT to host the content for free.