[sjs382]

On Stadia, games are rendered/run on Google servers. Nothing is running on the user's device. From the device's perspective, Stadia is just an app to capture gamepad input, send it to Google servers and play the video response (AV1, VP9 or h264).

[gmantg]

Even simpler: Stadia is the remote desktop rebranded. Want to run your own Stadia? Buy a bunch of VMs on some cloud hosting provider: a few for the game server engine and one per user with game client code (those need GPUs); then let users remote desktop into the client VMs. Did I miss anything?