I don't know if there is already some light sensor in the car but on my 2015 VW Polo (which doesn't have automatic headlights) if its too dark outside (even in daytime, due to bad weather or early nights) the lights of the dash are dim (you only see the needle of the speedometer and tacho). So there is still the obvious cue to turn them on. Perhaps its more common in European cars?
It could take a while to develop, on Mastodon it took about 2-3 years before folk started tooting about cars (now there is quite a lot of traffic). Also this sub seems quite US-centric, us Europeans see all your big trucks and muscle cars and think nobody will be interested in the superminis most folk drive round here, and a lot of people keep their cars stock as mods are expensive due to extra insurance costs!
I drive a modest VW Polo 6C myself (this is like 90% of a Golf, just slightly smaller) and am quite into detailing, I'd post up more pics but it keeps pissing down here in England at the moment (whilst rest of Europe is roasted by sun so there are often hosepipe bans!)