I’m just an engineer who dabbles in the “deck arts”, but it seems to me that having a backup system in place that doesn’t rely on satellites would be prudent. Any institution capable of putting a satellite into orbit is also capable of taking removing one from orbit, particuallarly if you don’t care about collateral damage. Wired mag wrote an article in '02 that includes half a dozen ways that a lot of space capable governments could implement. Same with the argument to get rid of c-nav from licensing tests, what happens if GPS isn’t there? “Oh, we have piloting for that.” What about all the water in between?