I decided to buy a full size truck in 2015. Decided on a 2015 Ram 1500 4x4 - wife said go ahead and get one with more options so we got a Laramie - very nice. Fast forward - guess who drives the full size truck - my wife. We have two grown kids and first grandchild. That truck has been in perpetual motion helping grown kids buy houses, move, etc. Filled back crew cab area plus bed taking toys to grandchild for Christmas. I agree that in theory you could plan exactly when you want/need truck and rent but I cannot begin to count the trips to Home Depot, Lowes, Costco, Sams, and so forth where the truck was used on unplanned or short notice.
I have a high mileage 178k 2006 BMW X5 still going strong but I suspect I will get an all purpose vehicle and Subaru Outback is looking strong for that role.