It's probably a viable business, given the location -- they probably sell a small fortune in bait, beer, and gas. As long as you could get reliable employees, you could probably make money at it.
They own the buildings, but not the land -- it's a forest service lease. This means when the forest service lease is up, the forest service can either opt to renew the lease if they feel it's a good use for the land or if they DON'T renew the lease, the owner of the buildings is financially responsible for removing them and returning the property to its natural state.
Considering this is a riparian setting, "returning the property to its natural state" could be an expensive proposition indeed if there's any pollution or damage to the creek found. (They sell gas, right?)
It's a crapshoot as to whether or not the forest service would renew the lease. From a practical standpoint, Tortilla Flat NEEDS to be there, because of all the folks who do things like forget to gas up, forget their water, get hungry, need a phone, car's overheating, etc. and ad nauseam. It's the only store along th Apache Trail until you get to the lakes, and there's a real need for a concessionaire there. I can't imagine this will change in 20 years -- AJ will probably be built out right to the edge of the Supes but from that point on, it's all wilderness.
OTOH, who knows what the environmental ethics will be? For all we know, in 20 years, the "leave no trace" ethic will be expanded to the "remove all traces" ethic ... and the forest service will want Tortilla Flat out of there.
Another concern I would have, incidently, is that Tortilla Flat has some serious flooding problems iirc my state history correctly. It's been a "town" (not incorporated) since the 1800's, but I do believe it's been scoured down to bedrock a few times by flooding. They may or may not have moved the town afterwards; I can't remember and I can't find the right book on that.