On a similar note, I've always wondered why when MP3 players started to become popular in the late 90s and early 2000s but cars were still stuck in the tape/CD stage, no car offered a stripped down entertainment system with just speakers, amplifier, and a 3.5mm jack.
Because way too many buyers would be put off by that and not buy the car. Sure, some young technically-inclined people would have liked that option at the time, but most buyers would not have.