I’m not that familiar with the Powerwall ecosystem, but the equipment and installation that connects to your breaker is non-trivial. But I’ve seen people who add bulk OEM batteries to other home backup systems and those are fairly cheap.

Regardless, the thing that’s really great for cost effectiveness is that the same large battery can be used everyday for driving and also used rarely for emergency home backup systems.

Its still a margin issue. The Powerwallproducer wants their 20% margin, the car company might want there 20% too, but from the whole truck.

The battery installer probably chargers a 100% markup.

10% to pay for their costs - materials and labour

90% to pay for their new Cybertruck financing

More like the people buying electric trucks got incredibly good deals, which is why the trucks are all going out of production.

You want at least one actual PowerWall so that your house doesn't go down when you take your truck on an errand. But yeah, if you're buying 4+ PowerWalls you're probably better off getting an EV with V2H capabilities instead.