>Newer cars have advanced driver-assistance systems, which can keep cars in their lane, detect blind spots, and avoid collisions—functions that require a car to have a firm grasp of where it is in space. That requires repairers to calibrate the sensors and cameras in a car underpinning those advanced systems.
I can't speak for all of those systems, but things like 'electronic stability control' (required in 2011) saves an estimated 2000+ lives every year. Fuel injection is obviously a huge advantage over carburetors for reliability, fuel efficiency, and squeezing more power out of an engine. Even relatively simple systems like these require numerous sensors, computer-units, and aren't easy to diagnose/fix for a shade tree mechanic with basic tools.