> 1. Imagine if Amazon starts building datacenters for others as a service

Just as an FYI, those fancy datacentres you see on Amazon/Google/Microsoft marketing videos are really the exception rather than the rule.

You will find the majority of cloud servers in exactly the same third-party datacentres that everyone else uses.

Why ?

Because only the US and perhaps one or two other countries in the world has the spare land for a cloud operator to dump a massive datacentre campus on.

Most other countries don't. Or if they do, its either protected land (greenbelt etc.) or its uninhabitable (e.g. Australian Outback).