The figures might add up now, but won't necessarily in future as the support funding for becoming an academy is pulled away in years to come.
Also, schools that find they can get loss-leader deals on things they need outside of the LEA provision will very soon find that the companies they source from are actually after making a profit and the privately sourced stuff will soon come at a premium. Why should it be any different in a private market? So all the assistance from an LEA subsidy will be gone.
An academy doesn't have to consult the parents at all - or it "consults" with a figleaf of consideration but actually simply presenting a fait accompli to the parents - that is one example of the lack of accountability that is built into the academy system. Also once an academy they don't elect governors to the governing body, just "select" them - so a clique of like-minded yes-people can quickly build up and not be challenged from outside. There is only a requirement to have two parent governors: does this sound like "more parental say" in how our schools are run?
Once an academy there is no obligation to keep the the curriculum as they have promised - changes in finance and leadership team members can mean curriculum and teachers' pay and conditions can change and be differentiated very quickly with no appeal. The appeals process for parents with concerns becomes something handled at a distance, and less easily accesssible.
Academies have to pay for all their own overheads - legal costs, insurance, human resources, etc. Where will this money come from? They will receive a £25,000 grant to convert their status but the process can cost from £50,000 - £70,000 - where does this money come from?
Within the LEA, schools receive a prescribed amount of support for things like educational psychology, an amount which is safeguarded. Once free of the LEA, a school can choose whether it will pay for more (at private rates) or whether, actually, budgetary demands might mean that they actually source less support. Who will know and hold them to account for this kind of thing? In the LEA, a school will have subsidised schools' music teachers for peripatetic lessons, plus the musical instruments bank to support pupils' learning: how will this continue?
Academies are a terrible thing. The only slight benefit they might bring is a possibility of choosing where to spend the entirety of their budget. Do you trust your school to spend money in hand on needier pupils or to build flashy new teaching suites to impress the parents selecting their secondary school? To not alter the curriculum to attract certain types of parent/pupil and disregard other curriculum options? To dedicate funding to things like 'governor training' which is automatically provided by the LEA and crucial to have in place, for a well-run school? Or money for for staff development? Once free of control, academies can effectively do what they like and with no oversight or guidance, or transparency and no accountability other than to the Secretary of State, who, like, really gives a damn and who would be quite happy to see a private company come in and take over the school if things don't work quite right.
Those schools who are Outstanding who become academies are freed from being OSTED'ed ever again. There is no indication that other academised schools will have OFSTED's at the same intervals as they are currently held to within the LEA.
A great deal of the pushing for academies is not purely on the financial ticket alone - though obviously schools have to balance their budgets and many funding streams have been axed this last year; the pushing can come from leadership teams with agendas against other local schools (jumping in first to get ahead) or with career promotion in mind.
"The short term" was mentioned above but academies are for the long-term: once an academy, there's no way back into the LEA system. People should start thinking about the long-term - about this school or that school once their own children are through and out the other side; how the school will and can change its ethos, its curriculum, its employment terms for teachers of the same current pay grade and pension conditions. It will be able to do what it likes and parents will be powerless to do anything about it. And what're the odds on special needs provision getting the bum deal in all the re-allocation of funds and scraping around for the best private sources of all the things the LEA used to provide "for free"?