You’d be amazed how many problems can be solved when the people involved have legal liability. My first GPS unit was out of date from the moment I bought it. It wasn’t because keeping a map up to date was hard, it was because they didn’t care, you’d already bought the GPS and it was better than not having one at all. This isn’t a technological problem.
Your car’s GPS-localized speed map is wrong because no one cares enough to make it right, not because it’s an unsolvable problem. It’s a gimmick to get you to buy the car, and you already bought the car.