DRJAD / CZ
Great idea, mentoring, but one has to get this past the old grey-haired CFI whose view is likely to be "a student should fly only with a PROPER INSTRUCTOR othewise he/she might pick up bad habits".
A less charitable attitude on the school's part is that they want the student to donate every penny that he has to the school, and not to some other pilot's PPL cost sharing scheme
Given that many students are skint and can only just scrape together the money for each lesson, this is an understandable "business attitude" - hugely damaging to the PPL scene in the long run of course.
There are lots more things which a school could do to advance things; e.g. buy a decent plane and then sell off shares in it to keen pilots. This is even less likely to happen, for obvious reasons...