Having worked in good and bad academies, I think it's a bit unfair to judge so harshly. they do improve standards better and faster than most local authorities by changing the staff, the curriculum and practices. i worked at one where at least 10% of the staff would be off sick on any given day, expect to be paid in full for the days they don't want to come in to do the work that they would rather choose to do at whatever pace they chose. A member of the old SLT who exclaimed "you can't polish a turd" was offered a compromise to go asap and she was perceived as being counter-productive to student progress after 15 years on the job. On becoming an Academy, that was all changed and the school came out of special measures and doubled results in 2 years.
There's a lot more that goes on behind the scenes and needs to go on for the change to happen. As a result of propaganda, the new HT was threatened a lot, spat on by angry parents, had sit in protests including one where the parents carried hammers and chased away parents who tried to attend the prospective parents evening (police intervention required). Old HT and her staff shredded risk assessments, electrical certificates, staff contracts, electrical plans, fire plans and emergency evac procedures etc thereby putting students lives at risk. Local authority did nothing put whinge about the cost of making teachers redundant asking if they could be kept on staff to save money. Students ran riot and it didn't often occur to the teachers to rally them into class or impose sanctions for playing football on the field during lesson time.
Good Headteachers know what good teaching looks like and the biggest indicators for school success are good teaching and learning and good leadership and management. The NPQH program addresses the other skills required although it doesn't always work. Some local authorities are notoriously bad with educational standards including Basildon Council. I will admit, said academy sponsorships was questionable as it was one sort of american investment banker dude and the new principal is on his first headship which is a tricky combo.
One of the predecessor schools had almost always been in special measures and the council did not make any improvements. this was just an opportunity to absolve themselves of blame for the first time in the history of the school.
I suppose my experience is unusual but the academy route was the best way out and the local authority supported academy status at the time because it admitted it didn't know what to do.