Nothing forces them to; basic economics tells us that their prices will rise to the point that consumers will bear, and that subsidy increases the price that co

Nothing forces them to; basic economics tells us that their prices will rise to the point that consumers will bear, and that subsidy increases the price that consumers will bear. Recent research (http://www.nber.org/chapters/c13711.pdf http://www.nber.org/chapters/c13711.pdf) bears out subsidy as a cost driver, as well.