I think the issue is two fold. Most people don't have many merits so have to be frugal with them, and posts can get buried very fast. Even threads with worthwhile discussion happening where gems can be found they quickly get buried by dozens of users making generic one/two liners.
I don't think the first point is the issue. I agree that your second point is a major problem. If more good posts were seen and merited, then that would solve the first issue.