I believe most will agree with me that there is a high probability factor that people give merit to those who merited them in the past, therefore creating a merit ring.
This may easily happen indeed. Just imho the reason is not friendship or whatever strange relationship you'd think, it's more like certain people discuss mostly on certain boards and that's where they give and receive merit. Clearly they'll give and receive merits from other people with similar interests.
But if this is true, then such individuals are cheating the system
While it can easily happen that some would cheat the system here and there, I don't think that it can happen at a large scale, since people will notice more clearly and the scammers would get tagged.
there is no clear or postulated indicator that credits a post merit worthy
You're right. And this makes more wide the reasons people would merit a post; some would merit even a post for being funny, for example. But the main reason for merit remains the usefulness, which also may be seen different by different people.
Without the merit system, I can't imagine what the forum would look like. There won't even be any interesting subjects to talk about just shit posts flooding every board.
Not all spammers care about merit though. Hence we still have a fair amount of spam/garbage.
You are imho too focused on what others do, while your goal seem to be to receive yourself more merit. And then I'd say that you may be doing it wrong.
Posting more useful stuff - from tutorial to spot-on answers to people needing help - could get you more merit than threads like this. But you have only 43 posts, so there's still plenty of time to improve.
The forum is not perfect, but it's great. Enjoy your ride!