Considering the fact that a lot of people here already tend to underprice heavily their products encouraging customers to ask for way too low prices most of the time, I think it would have for result to get the prices even lower and lower, and give CGT a reputation of cheap selling place : it wouldn't compete against Turbosquid anymore but would become some sort of generalist renderosity (which it already is to a certain extent). I don't think sellers nor even CGT has a whole would benefit from this, thus letting Turbosquid almost alone in the high end market.
Because if you open price rating to customers, especially newcomers in the 3D area, they will most certainly think that everything is too expensive. Just look at the job offers : how often guys are asking for complicated work for 10 bucks or less ?