A more important and useful thing to understand is that merit is measured by rules that bubble out of social systems.
A mistake you can make is to believe the the rules of merit that you believe are the same ones others believe, that the ones they state are the same ones they actually believe, that the rules don't depend on context, etc.
It's hard for people to accept this because we're taught that merit is an inherent quality, we may internalize the rules of merit we learn, treat them as constants, and then build our self-images based on those rules.
(I'm not suggesting to give up on the idea of merit altogether, but you'll do better to think of it as something you achieve for personal satisfaction and not necessarily expect external rewards.)
BTW, the rules of success (beyond the most basic stuff) are also social constructs, but they are different than the rules of merit. It's a mistake to expect them to necessarily be harmonious or consistent.