Just checked my fiber connection and it has 2ms of latency. google.com is 18ms away. I'm in Portugal and seem to be routed to a Google server 400+ km away in Spain. So my memory of playing on 10-20ms to local servers in Portugal is probably accurate. Covering the US or the EU with enough servers so everyone is never more than 30ms away seems feasible. Within easy reach of a startup with just ~50 VMs across different cloud provider locations and for popular games easy for users to setup regional servers themselves.