Hardly a stretch. The comparison isn't to the power density of gas, but overall curb weight. EVs are roughly 10% heavier than an ICE equivalent. Batteries are the main reason for that (electric motors and the electronics to support them aren't that much). Batteries have also been improving Wh/kg by 5-8% per year. It only takes a few years of improvements to get there.

In fact, since the 10% number has been the case since around 2020 or so, the battery tech might already be there and we just need to get them into new models.

Edit: another way to think about it is what's been taken out of an ICE and replaced with something else. It's not just the engine, but an entire engine life support system. Coolant radiator, oil, transmission, gas tank, and ignition system. Possibly differentials, as well, depending on the electric drive train. It's replaced with motors (which don't weigh much for the power they output compared to ICEs), some electronics (which do need to be beefy to handle the current involved, but also don't weigh that much, relatively speaking), the battery (major source of weight), and the battery does usually need a cooling system, as well. So you don't need to compare it to the energy density of gas, but of all the stuff you replaced.