>It implies a defensive structure. I.e the advantage I get out of low status.

OP is using the term moat in the standard way, actually. Something you have to cross to get to the reward (skill at a particular thing), that most people won't pay the cost for (being temporarily bad at something and low status). It stops most people from even trying to compete.

Quote from the article:

"It’s called a moat because it’s an effective bar to getting where you’re trying to go, and operates much like a moat in the business sense — as a barrier to entry that keeps people on the inside (who are already good at something) safe from competition from the horde of people on the outside (who could be)."