Most dealers take trade-ins at auction value so they can just sell the car off. Some cars that aren't running may still have decent auction value, while others will have no value. I'd suggest going to a car forum specific to your vehicle and see what types of repairs are needed as mileage comes up, especially related to drive-train issues.
I was a Land Rover fan for many years and they always had engine issues over 70,000 miles to the tune of $6000 repairs but I learned to replace my own head gaskets at home for $200 in a week (or two). Did the head gasket repair 3X on 3 different trucks saving me $18,000 all for the cost of $1000 in parts and sometimes $20 in beer for mechanically inclined neighbor friends.
I'd suggest working hard to set aside money towards a drivetrain repair if needed. It's frequently better to repair a car than replace it -- even in some otherwise costly repairs if it means you can get another 50,000 miles out of it! All of my Land Rovers I repaired myself went another 50,000 miles with no issues before I sold and replaced them.
