> you bought one and had an accident that totals the car but oops, the steep depreciation curve means you have to go out of pocket to pay off a total loss

That can happen with a conventional car as well, which is why gap insurance exists. The regular insurance should still give you the replacement price (which would be the depreciated value).

The gap insurance will be more expensive. Resell still matters with gap insurance.

Yes but again, the steeper depreciation curve makes it more likely to happen.