Unfortunately, most categories like the bitcoin discussion forum, economics, gambling and other relevant titles contain threads that are too generic and common, perfect for individuals whose purpose are to complete their required quota under the rules of their signature campaign. Unlike here in the Meta section, most discussions (like this one) revolves around the discussion of actual things that happen here in the forum and not some poorly-made threads.

Generalising that the 'merit system' failed to do its purpose is too fallacious. No system is perfect. If there exists a perfect system in the world, I doubt that corruption and chaos would occur. While the merit system cannot fully answer the problem of shit posting and spammers, it at least mitigated the damage and added a new type of reward wherein people rank-up depending on the usefulness of their replies. Hope that clears any ambiguities you have in mind.