A thousand activities for a merit doesn't sound so motivating to me or anyone without merit for that matter and  I have seen certain top members that hasn't reached that mark. For me i think the problem is that some unmerited members are yet to come up with good posts and some who has unfortunately go unnoticed and when such posts are not noticed it doesn't get merited. I think the merit sources should go over threads from time to time to see these posts in order to merit them.