If there is an unclassified American ape, then we ought to have better footage than we do. Even if the Patterson-Gimlin film of 1967, considered the gold standard by those pursuing sasquatch, is genuine, the millions of camcorders and smartphones in the USA should have yielded something better than an endless array of "blobsquatch" images. (Someone suggested that the cameras are fine, but the sasquatches are blurry.)
This author makes the case that images of a smart, shy animal that normally avoids humans are very hard to get. There are only a few sasquatch hunters in the field at any time, and people who meet a huge animal by accident are likely to be too startled to reach for a camera.
You can draw an analogy with pumas: we know there are thousands, but good photos or videos from surprise encounters are very rare. (I think that's better than the anology about drive-by shootings the author emphasizes, given that there's an active intimidation element behind the rarity of drive-by footage.)
I'm not entirely convinced (think of the millions of birders who wander out with cameras, for example), but this is a well-reasoned argument.