A distinction needs to be made.
Two types of cadetships:
1. Qantas and Air New Zealand
2. Rex, Jetstar and Pacific Blue etc.
Group one is a cadetship based on extracting high achievers from the general population and seeing them as a 40 year investment.
Group two is a means to an end. Get a bum on a seat. These types of companies have trouble attracting the cream due to their woeful and pitiful conditions. These schemes are purely based on lowering conditions and extracting money from hopefuls.
Please don't confuse the two. QF have been doing the cadet thing effectively for years. You could possibly compare the first group to the armed services.
Apples and Oranges.