What you're proposing is an insanely restrictive policy which is aimed at protecting the ability of people to earn money from the forum.  You're essentially prioritising what should be a nice side benefit of the forum over its primary function.

If anything, I think it creates another problem.  It will discourage people who just want to use the forum from using the forum, and that's not the intention behind the merit system.  You don't want to introduce even more rules or metrics which discourage people from using and contributing to the forum as a community.  That will just mean that even more of the remaining members will be here purely to earn money from the forum and wherever you set the bar they will make the bare minimum effort necessary to reach it.