Actually, Danny, it's because the 20 doesn't belong to the Colorado Railroad Museum.
The 20 belongs to the Rocky Mountain Railroad Club, as does the D&RG 0578, the Rico, and the trolley cars that used to reside there. I think that the Museum would rather spend their monetary resources on the equipment that belongs to them.
Whether anybody likes it or not, the 20 will either sit and rust, be restored, or be Saran-wrapped at the whims and wishes of the Rocky Mountain Railroad Club and not the Colorado Railroad Museum.
Rick