How many people do you know with the time to set up their own school? One important footnote in the Conservative education plans (which I wouldn't know if it wasn't for Dolph pointing it out) is that they will allow private companies to start up their own schools too, so far from being parents setting up their own school it will be parents asking a company to do it for them.
Just out of interest, why do you think this is worse and more prone to abuse than the vampiric and unnecessary LEA system?