I played a lot of golf at these courses in the 80'- particularly Randolph and Fred Enke.
A few thoughts:
1. The cited standard of 1 course for 50K residents does not make sense in Tucson where the population probably at least doubles for a portion of the year.
2. If one is concerned about growing the game - these are exactly the types of courses that can do so.
3. There probably are too many courses in town.
4. Losing Silverbell seems like no big loss to me. The course stinks and there is plenty of golf in the area. I am not sure whether the county course still exists but it is a better option that serves the same type of customer base.
5. El Rio is pretty interesting. I think it hosted a tour tournament at one time. It is in a terrible neighborhood. It would surprise me if a housing development could do well there unless one razed the surrounding neighborhood. If there was one course that would be a candidate for an interesting restoration, El Rio would be it.
6. Fred Enke seemed like a good use of property that would not be used for something else. It is surrounded by an air force junk yard. It was always pretty cool to look at the rotting planes while playing. Perhaps the city has grown out that direction but it was a long ways away from anything other than the air force base when I played it. The course itself is a strange one for municipal play because it is very much a target course.