I have 55,000 miles on my 2017 F-150. It has the 5.0 engine. Overall gas mileage is 19 MPG. I'm still running the tires it came with, Goodyears, and they look to be good for at least another 10,000 miles or so. They have been rotated every 5-10,000 miles.
If the truck in the OP is in that bad of shape, I'd say it's not Ford's fault, but neglect from the owner.
