Cart, Horse, Horse, Cart...?
At my school (London area) a full-time FI is lucky if they take in 12,000 pa; some have other businesses on the side, some drive cabs in the evenings etc. to make ends meet. The main reason for this is that the same school will happily take advantage of part-time weekend instructors who are content to work for nothing. However, nobody can live on fresh air, and the result is that many schools find it hard to operate profitably on weekdays because few can live on the meagre wages on offer.
If the industry paid living wages then young wannabes would stick around and older, more experienced instructors would be able to afford to offer their services full-time. And I don't buy the argument that if instructors were paid more the industry would suffer. I know what it costs to operate a C152 and I know what the lessons are charged out at - the margin is well over 100%. I don't think the hourly pay rate at my school has gone up in the past 10 years but the price of lessons certainly has.