Not to mention wireless networks like the ones for the airtag or the wifi endpoints mapping google has could be adapted to share positions of "right here, right now" anonymously.

Which means that if only one device knows where it is, you can calibrate, and if several know, you can even correct for mistakes.

If the system is precise enough, you only need to calibrate once in a while. Being at home/office, on the local wifi, once, could be enough.

Besides, nobody wants the GPS to go, but it's a nice alternative that can't be jammed by enemy forces and can be used for hiking, diving, etc.