I don’t think there is a ton of spare capacity. But even if there was the machines are designed for AI not gaming, e.g. low CPU clocks, the GPUs don’t have RT cores or video encoders, etc. Stadia had custom hardware, GeForce Now uses workstation GPUs, xCloud has custom servers. Gaming also isn’t a good use for spare capacity. Demand is very spiky and people don’t have a lot of time flexibility.