Why not go ahead with your darkroom, Chuck? Film and paper is likely to be available for many years to come, even if some players drop from the field. To re-use your analogy, some of the dogs have restructured themselves such that they are easier for the tail to wag.

I like to equate the darkroom investment to buying a car. We spend spend [whatever] on the new car, use it for 3 years, and end up with something that's worth 25-30% of what we paid, even if we ignore the cost of interest on the car loan. We look at the net expense as acceptable, based on the utility of the transportation provided, along with whatever pleasure we get from driving the vehicle of our choice. A darkroom is much less of an expense, and the space can usually be converted back to its former use inexpensively, should our interests change.