[bluGill]

That is an invalid comparison. All we know is that the 4% of time those people spend in their car is to them worth a lot of money to them.

The costs of a car need to be paid. Rental cars need to pay the same costs. (probably more because rental cars tend to be newer cars, and also because people tend to abuse rental cars knowing that the cost will not be theirs.

Yes, if you rarely drive renting a car becomes cost effective. However we already have car rental companies and car sharing companies. The economics of them are something you can research if you are interested. It might or might not pay off in any given situation.