I’ve been wrong before, but even though I have and use the bodies, mostly Supers at this point, I doubt they will ever be worth more than they are today. Which isn’t all that much. The lenses are expensive now, and they very well might go up in monetary value, but that’s because they are great lenses, and can be adapted to mirrorless bodies.
The camera bodies are fiendishly complicated and difficult to impossible to repair. Plus they were prone to reliability issues when new, a fact which is generally considered to be responsible for driving Zeiss out of the camera business. If your Contarex works now, consider yourself lucky, use it and enjoy it while it lasts, would be my recommendation. There’s no cottage industry of repairers outside of Henry Scherer. He can fix them, maybe the only one still willing to do a CLA on these, but it’s extremely expensive and time consuming. If you look at an exploded diagram of that camera, you will understand why that is. That lovely whirring sound when you press the shutter release is the result of a lovely, fragile clockwork mechanism that was a little too complicated for its own good.
I love the lenses, though.
Anyway, good luck, get a nice lens and enjoy the camera, but don’t expect to use it as a nest egg.