I like the idea of one-way rentals of towable generators. Think a U-haul like model, where you pick one up at a gas station near your origin, and drop it at your destination. Now if EV makers would just allow charging while driving..

It's probably more trouble and cost than it's worth. How many thousands of dollars are you willing to deposit for the use of the battery?

You can rent a pretty near CDL sized truck from UHaul/etc for little trouble. This would represent less than the upfront cost of a truck from the companies POV. They’d only need to worry about the chance people don’t reuturn the batteries. That seems unlikely given the same people would have given all their info up front and are highly likely to need a battery in the future. Vehicle rentals are far more risky and still a daily occurrence.

I’m 100% certain the market could exist. Probably the difficult part is car manufacturers supporting it and possibly some engineering problems (low probability of problems I think).