Teachers are leaving the profession as fast as they can (wonder why) and very few new teachers are replacing them. There was an article on California's new teachers that said that 40% fewer students were certified to teach last year, and enrollments are down by 50% in teacher education programs. I am guessing this is not unique to California.
The average number of years teachers have been teaching, teacher experience, has plummeted. Because the curriculum is now such a cookbook, the new teachers don't really know how to teach, they just know how to follow the (usually ridiculous and ineffective) teaching recipe. They are ineffective, and they know they are ineffective.
Pretty soon, to hold onto a teacher with any experience, you will have to pay a premium. And to get anything that even resembles decent results in your school, you're going to need those few experienced teachers.
If you can't get cheap teachers, the profit motive of the charter schools falls apart.
Already it is becoming clear that the charter schools are incubators for poor, burnt out teachers who leave after a year or two. And they don't get the results that public schools get.
This movement can't last.