Yeah, subscriptions and donations would have to be more than what is now. But distributed and federated systems and not chasing profitability at corporations would go a long way to running systems. Lemmy for example can be an alternative to Reddit while running off of hobbyist and donarion run servers. Gmail probably costs a fortune but what about 100,000 small independent email servers taking its place? Email is already a federated system. And then there’s self hosting. I bought a second hand computer and run the equivalent of Google Photos for myself and others on it for very cheap. Putting all these together, and if these were the default and more supported, the infrastructure costs can be spread thin.