> FCC regulates satellites launched from or communicating with the US

FCC is easier to deal with than multiple layers of environmental, planning, power, and water concerns at the local, state and federal levels.

> they're not obviously favourable compared with cold place on earth with clear skies and access to cold water

There are fewer of those places that can be developed than there is space. The bottleneck to space is launch. The bottleneck on the ground is power.

I don’t think anyone thinks the math works right now. But as OP showed, it’s surprisingly proximate in a way SBSP is not.

> FCC is easier to deal with than multiple layers of environmental, planning, power, and water concerns at the local, state and federal levels.

If you get fed up of multiple layers of concerns and US specific bureaucracy, you simply move to a different country where a single authority is desperate to not only remove hurdles but might even give subsidies to someone that wants to employ lots of people to put up solar panels and give them a bit of surplus power and hot water. Chips and solar panels fit as easily in shipping containers as they do in spacecraft. The FCC actually has to handle the concerns of entities more concerned by the environmental impact of your megaconstellation because it's a 1km^2 wide missile travelling at 17,500 mph which much of the rest of the space industry is expected to expend propellant to evade where orbits intersect, which is a bit more concerning than 5km^2 of slightly less green fields and some question marks about water abstraction, and there aren't other authorities you can turn to. (Space is underregulated in terms of not having any practical traffic management beyond launch and spectrum licensing, but that's more risk rather than dream libertarian business opportunity; the FCC can still kibosh your project, you just won't get anyone clearing debris out your way)

Technically there is more space in space than Earth, but once you start factoring that convenient orbits for earth data transfer involve carving a high speed path which intersects with other spacecraft also moving at high speed and not all with as much control as they'd like it starts to look a lot less capacious. The Earth not about to run out of coastal regions with unbuilt land any time soon.

(SBSP has its own similar issues, of course)