The basic premise of the charter school movement is to keep kids in school longer and make teachers work longer hours for less pay. When the U.S. economy is functioning in its normal dysfunctional way, there is a general shortage of math and science teachers. A factoid I read somewhere stated that 50% of new math teachers in 2008 California were on waiver, i.e. non-credentialed. This corresponds to what I saw on the ground.
The point being, the entire charter school movement is based on, and can only function, in a deeply depressed economy when there is a short-term surplus of core subjects teachers. Unless people believe that top teachers like to work for less money and longer hours. The entire charter school movement is going to fall apart spetacularly.