re: Average car costs $31K, depreciates 15% every year, sits idle 95% of the time

same here. I have a Tacoma I'm going to run into the ground. It's actually still worth what I paid for it four years ago. (It's depreciated only $2k in two years and I got it $2.5k under book) I'm looking at a late 00's 4runner now (or a Ford Flex, I really like those..)
I don't see ever buying new or financing.