I've ran my own cloud gaming VM on AWS and with an enterprise connection (1ms latency to the AWS datacenter) it's been good enough to play multiplayer shooting games and maintain a positive kill/death ratio against those who play locally.

Maybe the problem isn't that it's impossible per-se but that the consumer-grade services underprovision their machines/bandwidth, or that consumer-grade gigabit fiber isn't actually that good (or problems in the "last mile" like using Wi-Fi instead of good old Ethernet)?