Hmm so then what about 99%? Is that also "not enough". How could you possibly know?
You seem to be mixing market forces with government mandate here a bit. Why not still allow 1% ICE and see how the market reacts? Maybe you're right and it would result in near-0 but why enforce 0 ICE?
It’s simply bad policy to create a situation where a lot of 5-15 year old cars get scrapped because nobody can find a gas station. The country is much better off when people scrapping cars because they can’t get gas are doing that to 20+ year old cars.