I am of two minds when it comes to deciding to replace a vehicle.
The Appliance: This is the car that is only purchased for the utility, to serve a specific purpose and nothing more. The way I decide to replace this vehicle is based on repair cost. If the cost of keeping it running for one year is the same as what you would pay for a replacement car payment then it is time to replace it. You are now spending the same amount of money but have a new, more reliable, and likely more comfortable car than what you had before. The economics of time lost at the shop and inconvenience mean you are actually winning by paying the same amount of money.
The Project/Passion: Throw logic out the window, it doesn't apply here. This is were you find classic cars, projects that are never quite done, and cars that have special emotional meanings to the owners. People with these cars will throw tens of thousands of dollars at a car worth maybe $4,000 (on a good day, with a full tank of premium) because it makes them happy. When do you sell this car? When owning it is no longer making you happy. Some people love the process of building a car, as soon as that is done, they will sell it on to a loving home and buy another project to build.
The question is which one is your ZJ? I can see both sides, one being that the rig is just another tool to collect experiences, when it stops doing that safely and economically it is time to get something else. On the other hand, if you love the rig and can't stand to part with it, maybe to accept the higher cost of maintenance and repairs because it isn't about the cost or reliability, but the emotion.
It looks like you've gone with the second choice. I love the render!
(On a side note, Toyota and Nissan both build their trucks and most SUVs in the US. Many contain more US-made parts than Jeep, GM, or Ford products. My XTerra is an American-made product and was made in Tennessee.)