We can consider another example where the for profit company holds the charter, but this is rare in most states. Another rare case, is where the School Board contracts with a group to provide all instructional services at a set price. In one instance, the group is a cooperative of teachers. If it finds the service unsatisfactory, it doesn't renew the contract. What the charter movement can test is new practices to discover what works for increased learning.
Charters are to try new ideas.
It certainly can be considered that conventional public education could try new ideas and be run more efficiently.