Let's not forget that this does cause some negative externalities. I like the idea of it overall, but I think we need fewer people on the planet (1bb max probably) and a more overall educated and wealthy population for it to be successful. You would probably also want to start with non "western" countries (including Japan etc.) because if you start with, say, the US and the EU, it would almost immediately become uncontrollable. It also doesn't factor in disruption in local communities, changing how others live their lives or how they afford to live their lives now. Some of the tensions we see now are directly linked to mixing of cultures (and subsequent local divisions). At least that's how I see it.