I have seen plenty a side mirror on today’s cars costing over $2,000 (US). Many has cameras (for avoidance detection) and/or radar sensors built into them. That and 2 (or 3) electric motors and heater element (deicer). Some of them contain antennas for the TPMS (Tire Pressure Monitor System), as well.
I ran read an article on a BMW that has 11 different cameras on outside of the car, for collision avoidance.
Personally, I think this is a way for government to spy on us (ok, I taken my tin foil hat off and placed it back in a hidden bin by my computer).