sure, you can get propane or diesel setups that keep somewhere between a long time and indefinably.

>You can't stockpile gasoline for a long time without stabilizer.

If you have a vehicle that runs on gasoline, you don't have to store gasoline for a long time to have a stockpile.

The cost of a few empty canisters is by far smaller than the cost of solar batteries, and putting gas into a vehicle in case of an emergency within a span of seconds rather than hours is a huge asset.

Not to mention: not everyone has space for solar. City dwellers are particularly constrained (as in: people who live in apartment complexes).