I'd put the chances at over ten million to one. There is simply no credible evidence that a bigfoot type creature ever existed in North America. Besides that....factor the number of individuals required to sustain a viable population and you'd probably have numerous incidents of Bigfoot roadkill anually. When someone kills one with his pick-up truck I'll believe it. Until then, it's almost as silly as the notion that a population of pleasaurs exists in a Scottish lake.
I don’t favor the bigfoot story one way or another...but...I do know that scientists, in general, and wildlife biologists, in particular, are pretty dogmatic and blind to evidence contrary to the dogma they’ve been taught. A couple of recent cases in my neck of the woods come to mind...
Up until a decade or so back, Minnesota DNR biologist denied the possibility of cougars roaming MN forests. Of course, locals and hunters had been reporting sightings, but the official view was: tut, tut, you ignorant yokels - let the professionals tell you what is what. Well, in the last decade, a cougar was killed by a car and one was shot in one of the river systems right in the Twin Cities metro.
Case two: Last year a man was killed and partially eaten by wild wolves. Other attacks have been documented in the last decade or so, as well. Of course, literature abounds with accounts by credible outdoor people, indians and pioneer types of just this thing, but it has been boiler plate dogma for environmentalists and wildlife biologists to dismiss such accounts as not credible (...not scientifically trained, don’cha know!). Despite reports of increase wolf predation and attacks on pets in semi-urban settings in wolf territory, nothing changed their little, well-trained, scientific minds.
Well, now that we actually have some bones to pick, the reality now bears out what was common (or pededstrian) knowlege before. The arrognace works in reverse, too. Remember Strix occidentalis? Spotted owl for the unwashed. ‘Scientists’ were telling us all that the animal couldn’t survive unless they have pristine wilderness. So, the courts gave them about 27,000 acres per mating pair (according to defective population surveys). Now we know of course that this information was bogus, but, what the heck, we only lost half a million primary and secondary forest products jobs - but the important thing is that science has done its job well!
These kinds of episodes smack of the same thing to me.