Now, my programming blog makes enough through advertising and job listings to support me and my family, though I do have other revenue streams.
I suspect I am near the median.
I think part of the idea is that you also earn money off of products that result from the blog, as well as the blog itself. If your articles roll nicely into books that can sell, for example. Or sell t-shirts. Or if you have a webcomic with characters you can sell as plushies. All the little things add up to a living when you use the blog properly.
If that's what you want to do, those really famous bloggers are worth looking into, at least the ones who earned their fame as bloggers, but the ones who earned fame then became bloggers will have to do the right things, too, to make blogging pay off enough to keep doing that, as opposed to earning money off their fame in some other way.