The first point is that it is Statutory requirement for a School to have a website. Secondly, the school website has to include 15 statutory elements and more importantly, in almost all cases the website is used to communicate with the School Community, Advertise vacancies, promote success and achievements, publicise events, include blogs, video and photographs as well as trying to attract prospective students and allow them to apply for a place online - oh and most parents, carers and students will want to engage with a responsive website via their phones or tablets.
Very few schools have the expertise to create and manage their own site in the manner you suggest and I'd like to see a successful example of one where this approach has been taken.
