While licensing is definitely harder in Germany you also do not have to retest or do anything else to keep your license. It’s actually a problem that it’s pretty hard to take away the license from old unfit people (and the German government actually blocked EU legislation improving that).

When regulators make this reasonable. A lot of OEMs are interested in FOSS, but liability makes it hard - especially for safety critical domains.

Which at least in Germany should lead to failing vehicle inspections.

Doubtful. Android automotive OS runs on a single ECU in the car while a lot more are in there running QNX, Linux or some embedded OSes (sometimes there are more than 100 such ECUs in the car). So there’s no guarantee that the “problematic” services are even running on this ECU (I bet it’s more distributed). Furthermore updating / changing the software of a single ECU is done using special hardware or through some kind of gateway ECU. They will perform validation on the to-be-flashed software to ensure it’s from the vendor itself.

And even if you’d get it flashed I can guarantee you that nothing will work.