And to be clear, flat detection using slippage, dynamically calibrating to the actual tire diameter, is the cheapest way of doing it. Since flat detection is required by law, at least in the EU, every 10k€ new car sold in the last 5 years does it. Tesla does some marvelous stuff, but they also have some unbelievable inability to provide functionality that is nowadays just expected from a car.

In one of my cars (124 Spider) the method used to detect tire pressure actually depends on the trim chosen for that reason

I chose one that comes with performance oriented changes and interestingly enough that includes using a direct TPMS sensor in each wheel

Meanwhile the base trim uses an indirect system designed around the ABS sensors