Too much anecdotal evidence and personal experience , not enough hard facts to establish a list. I have found many old cameras not functioning at all or functioning poorly.

The key is really the knowledge of how to *thoroughly* check an old camera. Perhaps short of an instrument shutter speed test in the field, then at least a basic function test.

When on a camera hunt I always bring several common meter batteries, (the #675 zinc air hearing aid battery can usually be substituted for non available 1.35 mercury cells). and a small electronic flash with PC cord to check sync and, to an extent, lazy or capping shutter curtain problems. These checks will take several minutes and if the seller balks at the care I am taking then I walk away. Even with these precautions the camera could quit in the first month or two. That is the risk we all face.

In all of the above I'm not saying there are not some cameras that have not stood the test of time as well as certain others. The problem is that quite a few of our classic cameras have spent the last 20 or 30 years sitting around and not getting used. That is often times more detrimental to a camera than being used regularly over the same time frame.