I agree with most of what you said. This seems like an opening for tossing out a followup thought ..
This part has interesting implications. Unless the behavior is rooted in their DNA, this presents a puzzle. It's not just one bigfoot, or bigfoot in one area, that avoid us, it's ALL of them ... at least avoiding us to the degree they manage not to have good pictures taken or verifiable physical remains retrieved. If it's not hard-wired in the DNA it implies group planning and, to facilitate that, a symbolic language, not just grunts and hoots, as well as a communication means. Otherwise some remote bigfoot wouldn't get the message about avoiding us and would just walk into a hiker's camp to share a granola bar. Yeah, there are habituators who claim to have contact, frequent sightings, etc, but the details of those situations suggest a situation of **unlearned** behavior ... inherent conditioning being overcome, not avoidance conditioning that didn't happen.
We can't answer the question, we simply don't know, but whichever the answers is, it could well play into why we can't get that evidence.
Again .. tactics. You seldom win a battle of wits with an opponent you underestimate. We keep losing. I think that says something.
MIB