That certainly explains some cases, but it definitely doesn't account for all cases. I still distinctly remember a video someone made that was just reading a j

That certainly explains some cases, but it definitely doesn't account for all cases. I still distinctly remember a video someone made that was just reading a joke list that is widely spread across the internet. The delivery didn't add anything to the list. There was no reason to be a video whatsoever. A number of howto-type videos are the same way (while some really do benefit from a video, many more don't). I've even seen a few videos with no audio and the only content was text on a black background. My various problems with online video mean there's a lot of content from which I'm essentially cut off unless I want to put forth a special effort, and such effort is usually (though not always) not worth it.