I can only guess:
1) 2 1/2 election cycle means lots of money to be sloshing around campaigning, so someone may revert the decision of EV only or create some loopholes for the manufacturers to get around (carbon footprint trading, buying up emission credits all over the world to trade for, crushing old cars to create "credit" of new cars to be sold, etc).
2) Hybrids, so EV is ok and the buyer can "unlock" the gasoline engine through 5G by paying a pollution tax afterward, or the annual "smog check" will determine how much time you use your gas engine vs charging and you have to pay extra for that (or get a discount if you charge vs pump).
3) You can buy an EV and if you need gas you go to a rental car company to quickly "check out" a gas car for long trip, and rental car are exempt, along with commercial duty vehicles, etc etc. Everyone can drive EV most of the time and rent a gas car as needed (but you have to pay for more during long weekends).
4) Some accounting loophole you can "trade" an old gas car for a new one, like a core charge for rebuild transmission, but if you are buying a "new" car without a "core" you will be only buying an EV or you have to buy an old gas car to crush so you have credit to buy a new gas car, or some nonsense like that.
5) Some Chinese EV battery standard came along and people will just swap battery in at gas station if they ran out of charge, like Blue Rhino propane tank, limit to maybe 50lb each. They will likely get something like 60 miles per tank and if they are desperate they will be swapping tank every 60 miles, and they will pay a service fee and the battery charge delta between checkin and checkout, and no more range anxiety. Maybe they can make it to shape like a spare gas can so people can mount them to the rear of an SUV and look cool.
6) Every car company will have a trunk mount gasoline charger generator you can snap on to the back of your car for a long road trip range extender. Unlikely to happen if 5) becomes a standard.
7) Nothing happens, you just pay a "toll" and keep driving the same car we are driving in 2021. The cost will be high though.
It is all funny math, but there'll be loopholes and people will likely end up buying EV because it is the cheaper choice.