"Someone" told you wrong.
That probably was me, and I've brought receipts.
EVs represent 1.4% of the US vehicle fleet. There's a lot of cars in the USA. If you assume demand is linear and just added an extra 1.4% to the price of gas, well, that'd raise the current average price of gas by about $0.04/gal.
Granted, the real economics are probably a bit more squirrely if say, a magic genie showed up and granted the petroleum industry their wish that every EV instantly became a dino-juice burner, as the sudden surge in demand would cause a massive price spike at the pump. But in an alternate reality where Musk decided that drones to deliver fast food were more interesting than EVs, their gas prices aren't far off from ours (and they're getting burgers from heaven, so maybe it's not so bad).
From 2018 through 2024, about $16 billion was spent (or more accurately, mostly consisting of income tax money returned to taxpayers) on federal EV subsidies. Nice if it helped you afford an EV (raises hand), but admittedly, a pretty lousy bargain in terms of the amount of gasoline demand it abated.