Will prices of older Fujifilm cameras balance out when they normalize distribution of newer cameras?

My guess is "somewhere in between". Certainly short supply of new models is part of the reason for strong prices for older Fujis, but that's not the whole story. Fuji cameras have changed a lot over the past 4 or 5 years, with many models becoming much more feature rich and complex, more video oriented, and in some cases larger and heavier as well. These may be welcome changes for some, but for other longtime Fuji users who came to the brand for a high quality but relatively simple stills camera with full analog style controls, the new ones can seem like a bit much. There will probably always be some demand for the older cameras from fans of the original Fuji types.

I've bought two Fuji cameras fairly recently, one three years ago, and one earlier this month. The first was an X-T2, the second an X-T20. In both cases I considered newer models and decided that I didn't just not need the features of the newer camera, I actively preferred the older one.

I think I paid somewhere between $100 and $200 US more for the X-T20 than I would have 2 years ago. The smaller cameras seem to be in particularly strong demand-- when I was actively shopping after the holidays I found asking prices for used X-T20s often equalled or even exceeded asking prices for used X-T2s in similar grades. This could be because the X-T20 is in short supply, or because buyers are looking for a smaller, lighter, simpler camera, or some combination of the two factors.