> and zero accountability
That's simply not true, if only because most voucher schools insist their records don't have the same requirement for public access as at public schools. That's even less accountability, and accountability can't be negative.
> if you face inefficient system that cannot manage resources
Consolidated public schools exist because of the economies of scale. Break it apart into many smaller school and you lose that.
> as a proof you can
That is not proof. Get a forensic accountant on the case, look at the books, and identify the inefficiencies. Otherwise you can't dismiss the possibility that perhaps they are about as efficient as can be expected.
> academic achievement metrics
Which academic achievement metrics do you think are credible and appropriate? If a school spends a week on test prep, rather than teaching other topics, is that efficient? If a school does less music, arts, history, foreign language, etc. to focus on surface reading and arithmetic - the two tests which are cheapest to carry out - is that efficient?
> we just need to provide parents an option to opt-out of crooked system
That's been tried many times over the last 20 years. The resulting schools are not better, and the often even more crooked.
- only accept the students which are easiest to teach (no troublemakers, no kids with serious disabilities, no ESL students)
- if the school system pays more for students with disabilities, cherry-pick only those students with a disability which is easy to handle.
- use pretextual reasons to expel low-performing students, so your end-of-the-year test scores are higher
- have voucher school be a non-profit A owned by the same person who owns for-profit property company B and for-profit teaching materials company C. Have school A rent the building from B and pay C for teaching materials. Never report the finances.
- place requirements on parental involvement which can only be done by families with a stay-at-home parent. This biases the student population towards richer families, which are also well-correlated with good test scores.
- require additional tuition and other fees, again biasing the student population towards richer families.
- set up a voucher school in town where it's cheaper to teach, and let the public school handle transport for the rural school population
- define your catchment area to overlap with the richest part of town
And that list of real-world crooked policies comes simply from reading examples which have popped up on Peter Greene's Curmudgucation blog.