... except that in my experience most mechanics are competent with brakes, and most motherboard makers are not competent with cryptography, or indeed with anything having to do with software.
The auto repair industry has certain standards, and the computer industry... doesn't. In fact, the computer industry does everything it can to insulate itself from any kind of responsibility.
Because if they aren't and something happens the mechanic is the one who ends up rotting in a cell. Put the same penalties in place for ODMs and OEMs, mandating that machine owners absolutely always can change the locks to their own property, and mysteriously every single problem we have ever seen with secure boot is no longer some obscure inevitable unavoidable technology issue.
The auto repair industry has certain standards, and the computer industry... doesn't. In fact, the computer industry does everything it can to insulate itself from any kind of responsibility.