IMO, if you're selling more than you can provide, you're already doing it wrong...
It's not acceptable to prioritize some content over another when having the appropriate infrastructure would solve the problem.
> invest in bigger infrastructure and pass the cost down to consumers (which is not zero cost as you claim)
People will be paying for the product anyway, I don't see anything wrong with charging the cost of production/maintenance + profits (altough I suspect their profits might way higher than they should, and not being used to improve the ISP's as they should. I do not live in US though), that's what most other sellers around the world do and I really believe it's the most appropriate model.