I just bought a kit to convert to natural gas though. Most people who've done it are happy to not change bottles all the time. It won't help after an earthquake but the regular PSPS outages I get make natural gas a better fit for the moment.
It’s possible to get larger propane tanks and refill them more cheaply (rather than exchanging expensive grill tanks at the store). Some hardware stores will refill tanks directly. You can even get very large tanks (refilled by a truck that comes to your house) if you want weeks of power on tap. But this is probably overkill for most, unless you’re very remote.
This is a common enough occurrence in rural Louisiana, at least. And I think almost everyone I know has a 200gal or larger propane tank in their yard, specifically for multiday outages. My father-in-law doesn't have a single propane appliance, but he does have a 250gal tank, for his generac.
We don't we have a single 100lb tank, but that will run the little AC for 3 or 4 days.
This is important enough to me that I researched slow start AC units ~8 years ago when replacing my AC. I learned that almost any heat pump will do, so that's what I have.
https://hsph.harvard.edu/news/heat-waves-and-annual-death-ra...
In a traditional house with thick brick/stone walls and large roof overhangs you'd be uncomfortable but a lot less likely to die
Also, I built it myself so the labor costs aren't included but I am about $8k into a system (4kw of panels, 6kw inverter, 15kwH battery).
I personally wouldn't be able to make vehicle cheaper than having no grid tie. I get that the costs are different once you include labor. Also I am on 40acres so the panel set could be ground mounted.
But to make something commensurable with a propane home-powering generator seems a lot more do-able.
The quiter part makes sense, but there are a lot more practical solutions to that too.
A propane generator is a temporary solution but likely is good enough for most folks who just need to keep the fridge cold and maybe charge cell phones. It's not going to be able to run your house AC or anything, though.