There are dozens of car companies, so the market is working. Government regulation exists because your desire to buy a “simple” car impacts my ability to breathe. You can buy very simple vehicles for off road use.

Fixing broken cars became a cultural thing because cars really sucked and you had to waste a fair portion of your life fixing them. Things like emission regulation brought metrics and standards to the industry and resulted in better cars. The typical lifespan of a car is 2x what is was in the 80s (200k miles or 12 years).