Although I agree that some of the user-facing electronics in automobiles are overpriced, the core components use time-proven technology that is reliable. Even a low-end car (sold for less than $20,000) has engine electronics that are expected to last for ten or more years, an operating temperature range of probably 0 F to 120 F, and can withstand fairly heavy vibration over its lifetime. Your average computer or phone perhaps operates from 40 to 90 (although rated for much less) and would fall apart if put on a shaker. The electrical environment is relatively bad -- voltages range from 10 to 14 V and there are 4, 6 or 8 plugs firing off sparks. Some of the devices also are critical safety items -- for example brakes need to have redundancy and degrade gracefully if power is lost.
Contrast that to your average PC/Mac/iThing which is put into the market with buggy software and has critical patches every month.
For airplanes, cars and other transportation, I'd trade off tested and proven hardware and software for cool-looking flat icons on the touch screen.