The operational excellence required to have every successful Internet company manage deployments to a dozen regions just isn’t there. Most of us struggle with three, my last gig tried to do two, which isn’t economical because you always try to handle one region going dark which means you need at least 200% capacity, where 3 data centers only need 150 + ??%, and 4 need 133 + ??%. It has all of the consistency problems of n > 1 and few if any of the advantages.
We need more help from the CDNs of the world to run compute heavy operations at the edge. And if they choose to send them 10-20ms away to a beefier data center I think that’s probably fine. Just don’t make us have to have the sort of operational discipline that requires.