The sad thing is they don't need to close the attraction to fix the Yeti. Closing it obviously would be a convenience and get it done faster, but it could easily be worked on nightly with the ride operating the next day. They just choose not too. Why? Because people come off of Everest having had a great time. No tourist ever says upon exit, "man, the Yeti not working really ruined that for me!". So since GSATs are high, they have no incentive to fix the damn thing.