Old car is massive amounts of mechanotechnical engineering, with some software for keeping the beast under control and provide some basic entertainement.
New car is basically a computer on a simple chassis with an equally simple drive train. Software and battery tech is everything.
I'd argue that chassis tech is more sophisticated in the BEV case due to more weight. Adaptive dampers, air springs, rear-axle steering, etc. might not be necessary on a comparably sized ICE vehicle.
OTOH, ABS and ESP systems can achieve similar or even better results with less complexity because motor torque control is inherently low-latency, which can also complement brake deployment (hydraulics is not as well behaved as e-motor).
You do get rid of emissions control and tiny little sensors / flap actuators sprinkled all around the engine bay, so yeah, probably overall still a simplification win, but I doubt you can get very far without "massive amounts of [Mechatronics] engineering".
New car is basically a computer on a simple chassis with an equally simple drive train. Software and battery tech is everything.