I was planning to call this "Why Blogging is Easier than Vlogging" but that comes across as lazy and is restrictive. Headline deception!
If you can post Facebook statuses, you can use a Blogger template to run a blog. But there's so much extra work involved in recording, editing and distributing a video that it's prohibitive. Even a total technophobe can write their blog posts on paper and get someone else to type them up (though that doesn't make them a very true blogger).
I know badly-taken videos do go viral on Youtube sometimes, but they're almost always one-hit wonders. To consistently do well on Youtube (or another platform, I guess) you need a good camera, possibly a tripod (or, like, a stack of books), maybe editing software ... What I'm saying is that there's a lot more hardware needed for vlogging, and none of it is cheap.
Fewer Skills Required
As a blogger, you should be a good writer and/or funny and/or useful. If you're a vlogger, you still have to do all that (at least, I would - I need a script), but you also have to be a good speaker, preferably photogenic, engaging... It just really ups the barrier.
For a video, you need to keep in mind your background (i.e. clean your room), lighting, energy level, in-frame distractions. If I were to film a video at this time of year, there are only eight hours a week in which I could do it; It's dark before I go to school and dark when I come home, so since I need natural light I only have the middle of the day at the weekend. When I tend to be doing stuff. If someone comes into the room while you're filming, you have to either edit it out or start again (because sometimes it's impossible to edit out).
And then you have blogging, where you can literally do it in bed with your laptop on your chest, wearing pyjamas (or less), and no one has to know. You can write a blog post in stages, coming back to the document whenever you feel like it, but if you do that with a video people will notice the light/your appearance changing.
This is the biggest reason, I think. Editing a video is awful, because unless you're really good at it it leaves traces (and it takes time to get good, time in which people see your mistakes).
Now, I'm not talking about the difficulty of finding fault with your own work. That applies pretty equally to any creative work.
But backspacing is an awful lot easier than cutting a video, because the cut is visible in the final video (again, for the inexperienced. Famous vloggers have got this down, obviously, but they probably don't use Windows Movie Maker).
So there you have it, that's why I'm more comfortable blogging than vlogging. Vlogging seems to be more rewarding when you look at the teenage stars it's made, but I think blogging suits me a lot more. Feel free to agree/disagree in the comments.