Because their money as good as a no-lifer? People who don't feel like they can accomplish anything will stop playing, and player-retention is really the only metric that can allow for predictive revenue returns. A downswing in player retention will inherently lead to lower revenue.
Going back on your original complaint about the difficulty in the game, the game's designed to hit a certain level of mediocrity to have a rather wide customer-base. Maintaining interest, even amongst the no-skills and lifers, is paramount over making you feel special.