Actually, I think the flip side is even more interesting. If you want to give good, low latency service to 50% of the world you need a lot of data centers.
If you have an efficient website, you can get decent performance to most of the world with one pop on the West cost of the USA.
Well half of those cities were in Asia during business hours, so given that the majority of humans live in Asia it makes sense. CF data centers in Asia also seem to be less distributed than in the West (e.g. Vietnam traffic seems to go to Singapore) meanwhile CF has multiple centers distributed throughout the US.