I really think that good, iconic, classic film cameras are a good investment right now. I believe that film photography would be a niche not strong enough to distract the producers from digital war and make them developing new, cheap and good film cameras.
But the niche would be strong enough to keep up the prices of the good film cameras.
The beauty of this kind of investment is that you get to use your invesment for your enjoyment. It is treu that we sometimes try to support our GAS affected decisions by searching for "reasons" why we buy a certain camera. We don't need any reasons beside this two: 1. I have the money and 2. I need that camera.
I try a different aproach to fight GAS nowadays. I am searching for the ultimate camera, invest a lot of money in it and then stop. So I am hunting for a true user camera with a collectible value. Like a special edition Leica MP.