I totally agree with your rules here, however I recently helped my mom buy a new car (2023 Nissan Murano) and while sitting with her in the finance room deciding on warranty stuff I realized that cars are mostly 100 interconnected computers on wheels. This means the most likely thing to break on a car is a computer. This is something only the dealer can fix probably. Because of this you can’t get the same kind of warranty on a used car, only new.
The warranty my mom on this new car is great and it will cover any kind of computer issue for years. If she had gone and saved a bunch of money by picking a used car from the same year or 1-2 years old she could not get that warranty, and if a computer issue popped up years later it could be terribly expensive.