Thinking about it, for most of us, our enlargers, timers, etc etc live in the darkroom 24hr/365 days/yr. Our darkroom is open and running Sept to June, seven days a week, 8am to midnight -- and some use over the summer. 19 enlarger stations. We tend to wear out equipment before it ever has a chance to corrode. But I have several dead GraLab timers that seemed to internally corrode and that sort of thing over the last 19 years I have worked here.
There are some nasty chemicals that if the container leaks, it gets into the air -- then one has a rust attack on all iron-based metals in the room. Wish I could remember exactly what the chemical was (Sodium bisulfate? not sure), but a knowledgable photographer/lithographer/teacher friend of mine had this particular chemical eat through the metal lid of the glass jar of the stuff (original packaging) in his darkroom. The pull chains were flacking off rust, corrosion on his enlarger and that sort of fum stuff.
In the 30+ years I have been working in the darkroom, the times are too numerous that I have had temporarily uncontrolled water emergencies...things like water full blast through a long hose in the sink -- flaying all over the place! Even with one's hand on the control valve, it seems to take a long time to stop the waterworks!
So, I would say that displaying your collection in the open in the darkroom will reduce their lifespan. But it is up to you to figure out how much, if any, damage over time is significant. If you do not have the space to display them elsewhere, and they bring you pleasure to see them, then have them there in the darkroom with you. A good regular dusting/cleaning would be good -- if only to take the opportunity to keep and eye out for any air-borne damage. Small chemical spills that are allowed to dry would probably be one of the major sources of air-borne chemicals. Also when mixing powdered chemicals.
Perhaps some sort of display shelf that can protect the cameras from falling dust -- a sloping plexiglass shield perhaps? Less cleaning (and handling) of the cameras would be needed.
Vaughn