Very well then:
1. Every living organism, from Elephants to bacteria, leaves it own ecological impact on the environment. EX: a new predator is introduced into a large area full of deer. As time goes on, the deer population will start to decrease, due to the predator consuming them. Bigfoot, however, does not leave any ecological impact on its environment. There is no decrease in deer, elk, bear, plants, etc population, which you would expect if there was a breeding population of monstrous apes, which in reality there is no such thing.
2. Lack of remains- Every Animal, no matter how rare, has to leave remains behind. Scientists have no trouble finding a new species of insect in the remote, unaccessible areas of the Congo, yet no one can seem to find a population of hairy titans living in such close perimeters to people. The fact that nearly all of NA has been mapped and developed, yet not one finding of any large ape remains, makes the likelyhood of bigfoot plummet extremely low.
3. Lack of tools- If bigfoot has evaded man for all of these centuries, you would certainly expect tools and culture from such a smart species. The fact that bigfoot is never found, yet is described as smart as a bag of dirt, does not support consistency for it being a real species.
4. Every mammal, when giving birth, would be experiencing so much pain, which would make them scream their heads off. A sasquatch would require a huge voicebox, and if ever in a painful situation, its voice would certainly be heard for miles and miles.
5. Not all forests remote- Even the Dark, mysterious forests of the PNW are surveyed and mapped to death. Wildlife biologists and park rangers do travel great distances and cover so much land that any large species would be found by now.
6. Why so few sightings?- If this thing is real, it has to have an MVP (Minimum viable population) of around 4000. If this were the case, people would be running into these things daily, not once in every blue moon.
7. No consistent behavior- No one has ever reported seeing a bigfoot give birth, mate, or fight with each other, all of which you would see in a real population of a REAL species.
8. Bigfoot is reported in all 50 states, yet not one sighting has ever lead to good evidence.
9. Where the tracks lead to- A couple 1000 of these Hairy giants would certainly leave trackways behind. Don't you think that at least one trackway would lead you to your grand prize?
I am waiting, Mikey