A couple of other points……
How do the training aircraft affect student learning? If badly rigged, with instrumentation that is clearly not functioning correctly, dodgy radios, non-standard instrument layout, have been bashed onto the tarmac just one too many times, then rate of learning will certainly be affected. While subject to periodic maintenance, very many schools stretch the envelope when it comes to what is “acceptable”. Again, the impact is on the student who is subjected to adverse learning conditions, perhaps at a stage of training when not ready for them. So the school achieves a double whammy – the student pays for extra hours due to “slow” learning, while the school lines its pockets by skimping on maintenance costs.
How do multiple changes of instructor, often to suit a school’s other needs, affect progress? Commonly there can be little hand-over communication between different instructors for the same student on different days. Result – extra hours needed to demonstrate to the new instructor items already satisfactorily learnt on previous flights. The school earns more money.
Systematic exploitation and abuse of customers may not be too strong a description for what goes on