WiMax was the (pre)4G implementation using the old Nextel spectrum (a major reason why Sprint was an investor).

I had the EVO 4G on WiMax, had amazing speed, especially near the highways before anybody else did. Also made for a great hand warmer.

The point is that 5g may provide the product that most people want when they want fiber; have less additional infrastructure cost, and the wireless penetration doesn't matter if we consider a base station -- or a physical install (as required by fiber or coax)