Cars from the 90s up until about 2013 can be easily fitted with a $500 head unit upgrade, and support carplay quite well. With the right tools, it can be done in about two hours right in your driveway.
Cars from 2018 and up pretty universally support carplay, and it's generally quite well integrated into the car's infotainment system.
But, between 2013 and 2017, things were a complete mess. In-car systems were too integrated to be replaceable with a third party 2-DIN unit, but too primitive to run carplay/AA. People who have cars from this era either sell them (for less than they're worth, since only 21% of people will buy a car without carplay!) or put up with it for another 8 years or so until the car's wound out.
For example, my rustbucket '06 Toyota has a great sounding stereo with carplay but my sibling's 2017 Nissan is stuck with flaky and poorly integrated bluetooth.
Or, if you do want to upgrade your 2013-2017 car, you end up replacing half of the in-dash components with ones from a couple model years up, tapping into the car's CAN bus to recognize the new controller, and then running some sketchy scripts to patch the firmware to remove component protection since the VIN's don't match up anymore. Not for the faint of heart.