Regarding the searches, it depends largely on what the current status is. Are the dogs still picking up possible scents that they are trying to zero in on? If so, they will continue as long as possible. But once there is snow on the ground, this becomes more problematic. I don't know if they have eliminated areas because of scents or not. I do know that with the limited manpower they are using, it is possible in that terrain to miss something.
I do believe that she is out there somewhere, and I think she could have gotten a fair distance before the temps dropped below 20. But it is also possible that when she got cold, she found a little cubby hold to hole up in and try to get warmer, not realizing just how drastically the temps were going to drop. Or she found a place to hide, like the hollow trunk of a tree or something, which is what it has been said she does, and that place just hasn't been found yet. I think the odds of her being somewhere "not due to her running", as you put it, are pretty low. There was only about a 3-minute window in a remote area. I won't discount the possibility, and neither is LE, as they have said they are checking all leads, but it seems unlikely.
Like I said, I think she is out there. Unfortunately, the area is very difficult to search. And she isn't the first person who has gone missing in that area, and not been found despite searches.