A cloud server capable of gaming costs about $1 an hour. It has to be an on demand price, not a spot price because people won't accept their game being turned off arbitrary.
Don't get started with "it doesn't really cost Google $1 an hour to host a $1 hour server" because Google is forgoing $1 they could have gotten from selling it to a real customer.
Also cloud providers charge $0.10 a GB for bandwidth, and if the game sucks down 5 GB of bandwidth an hour we are talking $1.50 an hour.
If you play a game for 50 hours then you are talking $75 in recurring costs and that's before you pay for the actual game.
The "all-you-can-eat" plan is something that cloud gaming companies are offering now because it is familiar to people (e.g. the bloated cable bundle and Netflix following in its footsteps) and people just think it is natural and don't think "hmmm... is this a real business?" the way they would if you started writing down what things cost.
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What we know is that software devs use Javascript on the front end because they don't care how efficient it is (you are paying for it) but they use Rust and Go on the back end because they don't want to pay a dime more than they have to when they're paying.)
Thus with cloud gaming the cloud gaming company will always have a reason to Scroogle you with the hardware.
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If cloud gaming is really a scam to drive up the stock prices of companies like Google, or if it is an attempt to intimidate serious companies like Sony and Valve out of the business, the story that Google is telling makes sense.
If they think that somebody somewhere somehow plans to make money off cloud gaming that's another thing all together.