https://poal.co/s/Cars/591347/15ec8295-984d-408f-a8ad-fa37ce6cdf97#cmnts Because it provides full control over your vehicle and denies ownership to you. What everyone is moving toward is every part communicates over the CAN bus. This allows for part authentication. Meaning, if you didn't pay full fuck you price at the dealership, they will refuse to acknowledge your light bulb. Likewise, in the short term, before they can clamp everything down, this sets the stage to require "reprogramming" to allow your vehicle to acknowledge the new part. This is already standard for ECUs, engines, transmissions, 4wd modules, cabin control modules, and so on. Examples of this is, if you add factory fog lights to your vehicle, you MUST pay to have the serial number of the fog light's microcontroller programmed into the lighting control module. If you don't do this, your fog lights simply won't work without bypassing vehicle integration (different switch). In modern vehicles, almost nothing is actually a phsyical power toggle switch. Everything simply says, "hey, I'm serial number 1234 and my state is now [1 or 0]." The control module then says, oh, serial number 1234 is the cabin light. I'll now turn that on. Likewise, if it doesn't know 1234 (wasn't programmed), it says, fuck you, I'll ignore that until you pay the money we are extorting from you. Many modern vehicles already have identification as part of all lights (reverse, brake, head lights, running lights). Some high end vehicles already refuse to power up these lights if the address is not programmed into the corresponding controller. Or, they purposely cause a malfunction (example, tail lights constantly flash, indicating an error).