Well your other parts are correct but the actual number of people and thus number of potential players is where there is a huge difference when you compare west coast of US and whole EU.
I pointed it out earlier that even just France or Germany has more citizens than west coast. The total population of Europe, Russia excluded because I didn’t bother to check what proportion of them is located in western parts of Russia, is 508 million. West coast has around 57 million. You can see one rather significant reason why there is more demand on EU server than west coast server, right? Because there will be more customers, actually paying customers, here.
SEA and Oceania and bunch has lots of people too but they are third world countries where less people can afford to pay anything for their service.