For me it's that I don't want to be beholden to the car manufacturers schedule of updates or choice of features. The only thing that really dated on my previous car and tempted me to look at buying a new one was things like lack of bluetooth audio and no big screen for maps.
As an example, it tends to cost extra (at least it did historically) for maps in cars, I've also heard of having to pay annual fees for updates to those maps and even when the maps are "upto date", their information is still not as good as say Google Maps on your phone. So you land up with these expensive luxury cars, with huge infotainment screens, and then people still using a smart phone with its little screen on the side with its maps app simply because it's substantially more usable than what the car provides.
Additionally, each car manafacturer has their own version of media players and capabilities all with varying amount of features. They all insist on figuratively re-inventing the wheel, and landing up with one which is still way worse than my rapidly evolving phone and its apps.
Car infotainment systems these days should be little more than a largely dumb interface to my smart phone so that for the 10-20 years I own the car, I get regular updates on its utility as my smart phone and its apps improve.