Give it time, quality post will earn merits in the long run if it is deserving. It is a fact that merit is a limited resource and for this reason some users give it only to those they seem worthy of it and helped them. Those off topic posts that earns merits via merit abusing will be given red trust by default trust members anyway sooner or later, so don't be jealous of them. Rather, if your post contributes to the community, then just continue what you are doing. Those who do good post mostly are not demotivated in the situation at all, in fact some are challenged by it.