Why use such an indirect and backwards method? If you were in power, you could just tax non-green cars, rather than promote cars that become useless in 5 years when technology moves on.
It's a balance between doing what you want and screwing people hard enough to get voted out or violently deposed (transition mechanism depends on the system of government in question).
Sure, but second point is that it's dumb to assume "smart" or "connected" cars are more green. If they are being obsoleted much faster than "dumb" cars, then whether or not they are electric makes little difference in the grand scheme of things.
3G has been mainstream in the US since the mid 2000s. Granted it depends on when you purchase your car, but getting almost 20 years out of the technology is pretty good. Most cars will be scrap after that long. I'm not sure where you came up with 5 years.
Did you miss that cars are still being made that are 3g-only? And I’d be willing to bet that cars didn’t have 3g modems until long after 3g was first available.