If a camera were to fail (not from damage), it is usually the same part that goes. There are too many examples, from battery compartments deteriorating to prism desilvering, shutter curtains sticking. Just look at all the requests for help on this forum, many cameras of the same model have the same problems coming up time after time. And anything with electronics is pretty much a disaster waiting to happen.
One well-known and well-documented example is the failure of the AF motor in Leica S lenses. Leica subsequently changed the motor and the older lenses eventually need to be upgraded. Having a (very expensive) set of spare lenses would get you nowhere since they would have the old design. Similarly, the CCD image sensor of some of the early digital Leicas had a tendency of corrode. There are no replacements, there is no simple fix.