If they were to built it (and I SO doubt it will happen), they should cram in the best building possible. I'd be willing to pay $15 for a single trip up in the summer, just so I could access the upper-mountain trails without doing the entire climb. The Space Needle charges $13 for one trip up (or $17 for 2 trips)... and they do quite a business. I would bring out of town friends, non-mountain people, etc up there.
But then again, it has been talked about for nearly 40 years. I have a feeling we'll still be talking in 40 more. If the area is there at all.