There will be some EVs in that scenario. Enough to tide things over. But in a world with only one option, anything that blocks that one option will destroy the whole car industry.
But oil blockades won't stop the production of new ICE cars. A battery-related blockage will stop new car production. That would be a big crisis for automakers.
Again, the point is to not ban any kind of car as a redundancy. You've created an elaborate narrative of what you suppose your opponent is claiming. It is time to stop.