> So, in addition to mandatory physical controls for common functions, my imaginary EU legislation would also prescribe that all essential vehicle information (speed, outside light status, fuel level) has a physical representation (lights, dials, etc., in the sense that there is nothing that could be described as 'software' driving these).

We're way past that. All (to a rounding error) modern analogue dials are also controlled by software via the ECU. This has been true for decades now.

Few cars even have a mechanical throttle linkage anymore.