There are a lot of vested interests in preserving the status quo, and a change of this magnitude cannot be done gradually within a school or school system. The change requires a paradigm shift, from one in which external authority figures are in charge of the educational process to one in which each student is truly in charge of his or her own education.
The underlying beliefs about how children learn best are fundamentally at odds. As long as someone else sets a curriculum, no matter how many choices they offer within that curriculum, students will see it as someone else’s job, rather than theirs, to decide what to learn, and when and how to learn it. And as long as someone else is evaluating students’ progress, no matter how they do so, students will see that their job is to meet someone else’s expectations, rather than to establish and meet their own expectations.
You also can’t expect to eliminate evaluation gradually, one course at a time. Suppose you introduce into the curriculum one course in which students will not be graded. What you will find is that most students won’t do anything in that course, even if they want to, because they have grown dependent upon the reward of a grade. In a system where other courses are graded, the ungraded course is understood to be irrelevant. How can a good student justify devoting time to a course that is not graded if other courses are? In order to change that mindset, the whole system has to change.