Agree. Headlights are getting a lot more complicated they need to receive different inputs from different sensors nowadays like the rear height control sensor and acceleration sensor etc so it can adjust height / levelling. For adaptive headlights they need to read signals from the yaw sensor, steering angle sensor and speed sensors so they know how and when to turn.
But, like you say. It can be a lot more difficult ( and more expensive ) to find the cause of the problems now when compared to the simple switch, relay and lamp.