I was an early consumer back in the 90s and before Clinton authorized the government to unlock the precision. I have seen the evolution.
But remember too that the it can be disabled at any time. No doubt there is an on-off switch in the system. That is why people should learn how to navigate without them. That includes airplane navigation systems.
As a student pilot, I used to keep my old car GPS in my pocket so that I had a backup to the old navigation stuff on the Cessna 172 which had NO GPS. On one of my cross country solo flights, it saved my sorta lost self when I was south of the airport and I thought I was north of it.
On my sailboat, I had at least THREE independent GPS units since when off the coast out of sight of land, GPS had me spoiled very quickly. But I always had charts on the airplane and the boat that allowed a DR plot to be started if the electronics failed for whatever reason.
Selective availability is obsolete due to the existence of Glonass, Galileo and Beideu. But if you’re in a GPS denied area due to jamming or spoofing, you need backup systems ready to go.
Disabling GPS is a very difficult decision that would be the last step in a conflict. Worldwide GPS is used by civilians, more so than military, and if you turn it off then untold jets and ships and such would be severely hampered in their ability to operate safely.