“Cars these days are not so different from cell phones”.
Some of us still think of cars as a means of locomotion. They have become computer platforms with motors attached, and what this means is that tinkering has become much more difficult.
For example, a friend who is building a one-off electric car investigated the cost of tire air pressure monitors, which are mandatory now for any car you want to licence. He inquired of one firm that appeared to know what they were doing. Their price however was $8000 apiece.They build Formula Ones. He inquired then of the upstream supplier of that firm, which said that the price was 63 cents apiece, but he had to buy them in lots of 100,000. Out of generosity, the second supplier sent him a boxful for free, and said “let us know when you need lots more”.
Nevertheless, as more things become controllable only through proprietary software, the opportunities to check, repair or build machine for yourself are declining.