"skill" is not necessarily the same thing as "merit", but it's a lot more measurable. In general, though, the people most skilled at a given task tend to be the people who've been doing it the longest. The second tier of skill tends to be people who have been around people doing that task. That is to say, the most skilled people are generally current practitioners and their children, who grow up to be the most skilled people of the next generation.

In short, a "skillocracy" tends to look and act very, very much like an aristocracy, which is kind of the opposite of the idea I think most people try to express with the word "meritocracy".