What?! YES, the consumer! Maybe not YOU but the current products in the market ARE a reflection of what consumers want and are willing to pay for in their vehicles. If there was serious consumer pressure to simplify vehicle technology and reduce the number of processors then some manufacture would be pushing into that niche market and yet I don't see any commercials pitching the idea to forget all those other overly complicated vehicles and buy this simple technology-free vehicle.
Why? While the software in many infotainment systems is annoying and can be buggy, overall vehicle reliability has little to do with the electronics. Matter-of-fact, I can't think off the top of my head (I'm sure there are examples though) of ANY major catastrophic issues with any manufacturer that was due to a failure of the electronics but I can think of many cases where a catastrophic failure was due entirely to mechanical failure.