Having grown up back east (real close to Strasburg), I think another big difference between "Tourist Railroads" here and there is the length of the ride, and the proxmity to the ridership. Most of the time, the ride is typically 1-2 hours, and the overall exerience can be had in an afternoon. For families that want to wait to see "what the weather is like", they can typically just get in the car and go. With the large population base back east I would imagine there's a lot of walk-ups and few who see the need to make reservations in advance.
Contrast that with the C&TS or the D&SNG. Even if I lived in the area, at a minimum, it's an all day event. And even if you were coming from Denver, its going to be hard not to make it a 3 day trip. You need to plan ahead of time, figure out where you'll stay the night, etc. In otherwords, these railroads need to have a strong enough pull to get you to come. And the C&TS and presumably the Creede Line would have little else in the area to entertain anyone not enthused about the train ride (how about an Alligator Farm!).
So the entire experience from the time Mr. Tourist and family hits town till they leave has a big effect on the the operation's success. Granted there is a lot of traffic on US 285 and 160 through the valley. Maybe if there was a "short trip" option, there might be a way to pick up more riders on the spur of the moment. But the scenery right out of Anonito isn't much to brag about.
This reminds me of the Wyoming-Colorado RR Tourist operation. Great scenery, especially in the Fall. Right off of I80. But far from any large population base. Some support from the State of Wyoming, but zero from Colorado.
Result: track is gone.