As someone pointed out on the comment, one of the reason is Money, the other one is safety and security based on Vehicle manufacturer claim.

Yet, nobody can stop you to sniff and monitor your own car CAN/OBD2 interface using as simple as cheap microcontroller and compatible OBD2 interface kit (e.g CAN Transceiver/Controller kit).

EDIT: So far this curated list helpful to me for CAN bus based protocol.

Keycaps is where I always avoid because that’s what makes keyboard standout other than the overall produced sound.

Still saving for my keycaps sets

They def pricier on chassis, plate (foam too!) and ready-to-use designed pcb with components. However from my own experience building your own keyboard is fun especially when the result is as good as you expected from planning stage. Pure bliss.

Hello fellow 2hu youkai

Especially when they have luxury of lubed switches, foam, dampeners/stabilizers, custom case material (that keeb def. Custom one).

As someone that into mech keyboard hobby, I can say that’s still perceivable for average user as you still retain the familiar “qwerty” layout.

Look up stenograph keyboard. They have lesser keys but allows someone to write higher wpm and programmable though I don’t think they would fit for office environment.