That's the business of network providers. To acquire the hardware, install them, and operate the service. That has nothing to do with Nasa or Nokia.
I don't know why there are areas in US that lack service providers. Maybe someone here can explain it - I presume the reason has to do with something US specific about the business rather the overall cost since lots of low GDP areas globally can have good cellular coverage.
It's not so much average earnings per person as average people per square mile. The network providers only want to invest where the return on that investment meets or exceeds some floor. Parts of the US are so sparsely populated the phone contracts for cellular would be huge to justify building the towers and backhauling the signals.
I don't know why there are areas in US that lack service providers. Maybe someone here can explain it - I presume the reason has to do with something US specific about the business rather the overall cost since lots of low GDP areas globally can have good cellular coverage.