OK, let's go along with Kelly and change the rules of the game in the middle, after manufacturers have made their investments. Instead of ending the credits as each manufacturer sells 200,000 cars, end them immediately with total EV sales of 17,000. And instead of maintaining oil subsidies forever, or waiting until there are 250,000,000 cars on the road, end them retroactively when there were 17,000 cars on the road. Make the oil companies pay back all those years of subsidies. Revalue all the oil drilling grants at fair market value and collect for all the past decades.
Result. US debt greatly reduced. Gas prices go to $10 or $20 per gallon. EV's easily sell 200,000 next year without any subsidies. See, the free market can work if applied equally. :-)