If you can't realistically build an elevator, the question is meaningless. As for if you could build one, I don't know. Maybe, but chances are that an electromagnetic accelerator working in reverse could recover a lot of the energy. Also, it wouldn't be constrained by having to keep the upmass and downmass ratio bounded. And third, energy is really easy to come by on the surface of the Moon, so it's not like it would be a severe limitation.