it doesn't really matter how much the actual figure is. Yes $4,000 is a good amount...but if the company claims to offer the lowest CPM in the business, then that means that the publisher is losing out on the total money they could be earning by using other networks.

if you have enough traffic to make $4,000 with the lowest CPM in the business...then you have enough traffic to making $4,000+X with companies that have better CPM