> we’d have 24/7 live coverage of every inch on earth but do we really want that?

I think you misunderstand the maths a bit. If the goal is high bandwidth, which requires high density, for specific, randomly distributed, parts of the earth, then, by the fundamental laws of gravity and orbits, you'll also have coverage over the rest of it, whether you like it or not.

Just coverage is already provided by the 600-something direct to cell satellites already in orbit yes, but you need more if you want it to be useful beyond loading text-only posts or sending SMS