None of the presented solutions cover the aspect of being in a different place than the rack, the same network is fine, but at a minimum a different room.
How do you deliver high resolution (e.g. 1440p, 144 fps) to multiple monitors with low latency over a network? I haven't seen anything like that accomplished without running fiber from the host.
Eventually, your thin client will need too much power anyway, making the costs rise a lot. It makes sense in an office where you have 500 seats and you can load balance resources.
If someone can show me a multi seat gaming server that has native remote performance (as in you drag windows around in 144 fps, not the standard artifacty high latency behavior of vnc) I'll eat a shoe.