Consider 77 satellites, each catching [100 watts] of solar power that you perfectly turn into useful, information carrying RF, and then perfectly overlay so that the entire surface of the earth is covered. That sets available flux at ground level, You can't use more gain and not lose coverage area (location independent access). Now add users with omni-directional antennas. User antennas must not only be small but generally omni-directional - they have to see all the sky and can't be high gain beams constantly pointed (too big, too expensive).
The associated antenna aperture determines captured power. Because of system noise temperature (antenna sees terra firma no matter what NF the equipment has, S/N ratio is determined, thus due Shannon capacity of link is set.
Guess what, it's not much to write home about if you plug in reasonable numbers. A few users on each satellite can get a little bit but all users can't use it all (or much) of the time.
And we haven't even talked about backhaul, real-world efficiences etc.
This problem is akin to the problem of getting 3G or 4G mobile networks to work everywhere. They don't and won't unless the paths are shortened greatly and the density of points-of-presence (cell sites) is greatly increased.
n6gn