> A car can't power an entire household for days on end
This is underestimating the ludicrous amount of power an EV's batteries have. You can absolutely power your house for days on end using one. (Of course, that should also give us pause to think about what it means that we spend so much energy for transportation compared to household necessities.) And gasoline has plenty of problems too, like its extremely short shelf-life.
I have two Tesla Powerwalls in my garage, and they (among other things) do just this.
I look at the size of those, and the size of a random Tesla, and I can easily see two of these shoved into the baseboard of a Tesla, much less the larger vehicles.
I know the Ford Lightning was advertised as a potential back up power source for the home.
The real trick is getting the power out of the battery and in to the home itself. It's one thing to run an extension cord to the refrigerator, quite another to get the battery plugged into your home circuitry. That requires more preparation, as well as an electrician.
Cheap way to power the home directly is to get a generator inlet put in ($500-1000) and connect the vehicle to that. You can then use either a vehicle or a gas generator, which is useful during extended outages when you need to top up the car.
Expensive way is to get some manufacturer specific automatic transfer switch (I got Tesla's put in). The hardware is $2500 and the labor is $4K+.
I did both and used both during a recent week long outage.
4 bedroom house in Austin, TX. A hot summer is around 100 kWh and my Rivian battery is 135 kWh. Which means I can roughly get a one full summer day out of my car's battery (assuming I still need to drive the car and usually leave it at 70% max).
So there you have it, I get about one full day. Not "days on end".
On the other hand here in Washington a little west of Seattle with a 3 bedroom all electric house I use about 40 kWh a day in the coldest month of winter and 8-10 kWh a day in summer.
You could get something like a Span electrical panel and only enable critical loads during a blackout and set the AC a little higher than normal. Even a large house can go down to 20-30 kWh a day.
That's on the higher end of household usage. On the lower end, during a cold windstorm in the PNW I was able to get it down to 600W (15 kWh/day) because I have mostly natural gas appliances. My Cybertruck kept us going for nearly a week with just one top-up (because I don't like to go above 80% or below 20%). We deferred using the dryer and dishwasher, and relied on the fireplace for warmth instead of the HVAC.
On a hot day yeah I'd be running the A/C but ideally you'd have solar to offset much of that.
This is underestimating the ludicrous amount of power an EV's batteries have. You can absolutely power your house for days on end using one. (Of course, that should also give us pause to think about what it means that we spend so much energy for transportation compared to household necessities.) And gasoline has plenty of problems too, like its extremely short shelf-life.