Exactly.
I would not go as far as your statement- It is not uncommon to find deer and elk kill sites (I am in the Rockies). It is less common to find a moose or bear though, as their populations are much smaller.
But I will defend your comment in it's general sense. In particular I would point out that a carcass is naturally disarticulated in a very short period of time- In the course of a couple weeks all that is left is scattered bone and hair.
With the exception of the skull (which is often times dragged away), and considering the natural bias against crypto-zoological creatures, I find it quite plausible that the remains of such a creature might be misidentified by the non-critical eye of a casual observer.
Even so, it is the skull that would stand against your statement. Skulls can last for years in the wild, and especially the skull of a large animal. It seems unlikely that a skull has not been found in all these years.
It is also unlikely that one has not been killed by a hunter, considering the notoriety such a kill would bring.
That being said:
Once while I was in the deep woods I was awakened by a long mournful cry that raised the hair on my neck. The cry was repeated twice more and then fell silent. For the life of me I do not know what made that eerie sound, but my normally fearless dog tried to crawl into the sleeping bag with me, and spent the remainder of the night huddled against me.
Something VERY out-of-the-ordinary was out there.
That experience leaves me open to the idea of Bigfoot's existence, even when considering the odds against it.
-Bruce