One theory I’ve encountered is that trail cameras rely on infrared detectors for triggering, and that Bigfoot could see into the infrared spectrum.
Imagine walking through the woods at night, only to see a bright blue beam shining across the trail in front of you. Personally, I would avoid the blue beam, just on principles, because it looks out of place.
That being said, it is a certified mystery why nobody has nailed a good photo of Bigfoot, despite everybody carrying a decent (cellphone) camera and lots of alleged close-up encounters with the Big Guy and/or his wife and kids.
I like your theory about trailcams. Per phone cammys, I've learned one thing after living here in a national forest for two years... It's often very difficult to get the phone out and camera app up in time to grab a shot of unexpected wildlife encounters. I've seen many bear, Bobcat, turkeys, and beautiful woodpeckers, but only two photos so far. I dunno. It seems the more ubiquitous the phones are, the less blobsquatch photos there are - at all! Weird.
They would be immediately dismissed as fake. Most people I've heard of who managed to take fairly clear photos don't want to deal with the huge amount of negative media attention.
At best you end up with images like these, which can't be definitively established as real one way or the other. Scientists fall back on their old "Bigfoot does not exist because Bigfoot cannot exist" excuse and the photographer's story convinces no one.