The "just works" however should be only the outer shell, and if you want to do more, or if you want to learn, this shell should be easy to remove. As you can open your car and look inside, mess with it.
Instead many modern systems are designed to be blocked in the most basic shell, and to deny all the rest. Like the Apple iPad for instance.
It needs to be pointed out that there were legal struggles last century over the right to repair automobiles. Car companies didn't want third parties to be allowed to fix their cars. At the time, governments generally decided in favour of consumer rights to their own purchases and the benefits of competition.
As a disturbing sidenote, the "right to repair" issue has re-emerged with the computerization of cars: http://www.r2rc.eu/
Instead many modern systems are designed to be blocked in the most basic shell, and to deny all the rest. Like the Apple iPad for instance.