I think it's a combination of a lot of people are more biased towards watching a video than reading compared to some of us AND the fact the a lot of people find it a lot easier to narrate a video than it is to write a decent blog post especially if they also have to add photos etc.

I have a theory that half the population struggles with reading. They can read to get by but they find reading an article or blog post to be a struggle and certainly not entertaining.

Even if that's an exaggeration, I think there are lots of people who would much rather watch a video than read more than a paragraph or so.