....current cadet schemes are profitable for airlines who continue to offer the disingenuous suggestion of ongoing employment in a XX-group airline if you join (& pay) for
their course.
Exactly right! If airlines really wanted cadets schemes to provide a reliable supply of pilots, they would offer cadetships free of charge to suitably chosen candidates, with a bond period attached to the end of their training. “Pay-to-fly” cadetships are just another income stream for airlines who will take your money and offer no guarantee of a job.
As far as the “quality” issues. I’ve flown with people with diverse flying backgrounds, from a 20,000 hr co-pilot who had normalised hazardous attitudes because nothing bad had happened to him yet, to a 200 hr guy who appeared to have ten times that experience and an amazing attitude to match. It’s purely down to the individual and their capacity for humility.