Also, if we're going to start adding in the maintenance costs of rides (the behind-the-scenes type things) then there is brand new makeup along with the costume that needs to be applied. I know the costs are minuscule but it brings another factor to the equation.
I'd like to agree with your comment and take it a step further:
There are plenty of rides at all Disney parks that are based on movies and/or books that I have never seen/read. So long as the ATTRACTION(S) has/have staying power, then that's all that really matters. People 30 years from now...
My understanding is that it is a NextGen thing to do while waiting for the TLM ride. Scuttle gives hints on where to find things like snarfblatts (pipes) and dinglehoppers (forks).