Doesn't it seem odd that they would install a huge animatronic in such a way? I've seen commentary that the animatronics can be quite complex and need a fair amount of maintenance and yet the yeti is so hard to get to apparently.
Anyway, the ride is still a blast even with a stationary yeti.
The Yeti is different than most animatronics because it's mechanisms for movement and such are housed behind her in her "back". Most animatronics the mechanisms are housed in their legs and under their feet. They couldn't do this with the Yeti because of the sheer weight of the whole thing. She woulda crushed her own machinery. (Hope that makes sense.)