Basic micro-economics, that's all. if flying schools (i.e. employers) know that they can get someone to work for free, then they will recruit that person. If flying schools can't get people to work for free, then they realise they'll have to pay.
I stated a basic premise of supply and demand, sorry that you can't grasp the simple concept. It's a principle that works across all markets, not just aviation.
But it's OK for you to do it, just no-one else eh?
Cheers
Whirls