With all do respect, this is a false equivalence. I have looked at some of the posts you made, in particular that gained you many merits at once. And whereas you made undeniably fair and proper statements, gainig 30 merits for a short two sentences post, is disproportional, and has IMHO nothing to do with "quality". And please, don't get me wrong, I am not blaming you. I have received myself 10 merits for posts which I found completely undeserved, while other posts that I truly believed make some important, new contributions received 0.
What magic are you using to get so many merits even for short posts?

I have created a popular thread about privacy coins, but received only few merits so far. Maybe to get some merits one also has to be very lucky

It really has nothing to do with the length of a post. I actually find long posts annoying and prefer people to be able to get their point across concisely.
forum
NOUN (plural forums)
1 A meeting or medium where ideas and views on a particular issue can be exchanged.
we hope these pages act as a forum for debate
(Src: OED)
There is no secret or technique to gain merit, just use the forum for what it is intended. If you are having conversations and exchanging ideas then at least one person is reading your posts. Quality isn't about writing a masterpiece it is about making an important point.