Pretty much explained by the above posts, being this one particularly insightful into your specific case. Take it constructively, but many merited posts are not generated by a quick thought, but rather require the author to elaborate a bit more based on either his already pre-acquired knowledge, or cross-referencing reading different sources on a matter, in order to become more fluent in it. Generally speaking, conversations taking place in off-topic are not going to be of much interest, and subsequently, won’t postulate to obtaining merits.

Fun fact: You can, in fact, be re-ranked, though that is more of an anecdote, and takes place when posts are deleted by one or other party, to the point of losing Activity:
https://public.tableau.com/views/BitcointalkMeritDashboard/De-ranked?:language=es-ES&:display_count=n&:origin=viz_share_link