This is very inaccurate. The receiver doesn't output PWM, it communicates with the FC over UART. Control and telemetry are one link, open source, with a range of more than 100km on commodity hardware. Ardupilot enables advanced autonomy out of the box, DJI uses LTE for more than 20km range of HD video out of the box.
Sure, you don't have sensor fusion from a bunch of disparate exotic sensors, and the control software could be improved a lot, but it's not as bad as you describe it.
Sure, you don't have sensor fusion from a bunch of disparate exotic sensors, and the control software could be improved a lot, but it's not as bad as you describe it.