They have certainly become more complex to maintain when they go wrong. My current Mercedes and BMW have suffered with temperamental technical issues that simply would not have impacted previous cars because they didn't have the high levels of sensors the current ones do.
My BMW as an example has ongoing issues with auto full beam deciding it won't work on occasion, pedestrian protection sensors the same, outside temperature intermediately reading a 50 degrees which in turn impacts my internal AC for some reason. Recent issues with front nearside brake disk caused by a seized caliber pin and a tyre sensors system that determines what the pressures would be each time you start the car. 38psi today, 41psi tomorrow etc. This has been the most unreliable BMW and I think most unreliable cars I have ever owned, not least when you add in diesel filter issues.
My Merc has had 2 failed seat belt sensors, full set of engine mounts (they are clever dynamic mounts) and full set of dampers (another glitch). Never stopped me using the car and we all fixed under warranty, but annoying. Also, why is it when 1 car has issues the other car INSTANLY has issues. Seems you can never get to the point of "at least one of them is fine".
I really think the new BMW 5 Series is poor. Too big, hated the infotainment and felt lifeless and powerless in 2L Diesel form.
I do think manufacturers have cut conrners on materials, be that soft touch plastics and seat leather, just doesn't feels as good or has hard wearing.