As an example, my first paid instructing job paid £10 per flying hour. Given a 2 hour slot, to cover pre and post flight briefings it works out at yep you got it £5 an hour!
Now work that forward and say you do 500 hours a year, well work it out yourselves! it hardly covered the running costs of the car to and from the airfield.
Is it any wonder its seen as an hour building exercise until a proper job comes along. The schools offering these levels of pay really ought to be ashamed of themselves.