Lots of things in my house sit idle most of the time but I still have them because I do need them sometimes, so it’s a perfectly acceptable analogy. I don’t get what you’re saying about box trucks or boats either.
The cost of a leased or rented vehicle is quite a bit higher for me and many other people than the cost of owning. Not everyone is driving around brand new $40k cars. The last one I bought was $6k, and the one before that was $3,500.