These chickens are raised in this manor because of demand. I am sure the commercial growers would go back to a slower growing bird but consumers would stop buying chicken at the grocery store when the price of the bird over doubled. These birds were designed to be the way they are for a reason. It costs less to raise them. They are only in the world 6-8 weeks and the feed to weight gain is tremendous. They cost less per pound.
There are a lot of people that would not think twice about paying much more for chicken. I raise my own and I pay more than I could go to the grocery store and buy it. Same with eggs. But there are countless numbers of people that can hardly afford to feed themselves so cheap food is a necessity.
I don't like the ways things are done but as long as there is demand for cheap food, nothing will be changed. Companes that do cage free, organic, etc.... found a niche that they can make money on. Some people are willing to pay more but the majority just want cheap food for their families.