I have run across dozens if not hundreds of mistakes on maps in my lifetime, fortunately have been in situations that are life threatening.
I agree with the cautionary tale of not going into places like Death Valley relying simply on a rented cars GPS, but maps are no guarantee of accuracy. If anything the fact that GPS’s exist probably has helped make most maps more accurate as now there are millions of people daily using the data, and money to be made by making sure the data is accurate.
I have seen a huge improvement in map data in the last 10 years myself, because now they actually have folks walking and or driving the actual roads every few years validating the data that was on some survey map from 50 or 75 years ago is actually correct... often it was not. Paper streets, one ways, legal streets that are steps, etc etc... all of which 10 years ago would just show up as a road on a map but be incorrect or impassible by vehicle, and sometiems even by walking a paper street that never was finished which is now woods. etc etc.
Yes. biggest number of errors I find are changes in the use of roads. Around here when a road was mapped it may of had more traffic due to ranch use etc. Today the traffic patterns have changed to an adjacent road. I do wonder how many people submit problem reports to the mapping company. I do recall when the flurry of name changes to MLK this or that it took the mapping companies years to catch up.
I have seen mapping vehicles in the back country on two occasions. Once what I believe was a Google mapping vehicle was broken down in a very remote area in Northern Nevada. Stopped to help and the guy was not very friendly and said that help was on the way.