(1) I excluded gaming as something that is legitimately ping dependent
(2) You can achieve 100-130 ms latency with a "like one data center per continent" sort of network. You don't need edge computing on hundreds or thousands of edge sites to achieve that.
I'm sorry but what are you talking about? Fastly has about 60 PoPs (physical locations). No one is talking about hundreds of thousands of sites. Even akamai, who made it one of their primary marketing metrics, only ever got into the thousands.