I think the cadet versus experience argument is somewhat moot. I speak as someone who started as a cadet, who now flies with cadets, or their modern equivalent.
The problem, or potential one, comes down to the quality of people you attract to the profession. If the only people you attract into the business are ones whose mummy and daddy are rich enough to send them to pilot school, or who are so desperate to be an airline pilot that they will borrow huge sums, you restrict your potential "gene pool". That is not to say that those people are all bad, but you are missing out on a large number of people who simply can't afford it, or choose another profession.
Sadly, just really, really wanting to do something does not necessarily make you any good at it; sport is a good example. I wonder how military operations would fare, if the only people they had flying their toys had stumped up the money to fly them?
Yes, when I started, I was wet behind the ears, and had to learn a lot very quickly, but presumably, the selection process I'd been through was designed to make sure that I'd at least have a chance of coping. I know, nowadays that the standard of applicants to my airline is lower than it used to be. We, at least get to skim off the top, but there just won't be the same numbers of quality people coming through, if a) airlines don't sponsor, and b) the potential rewards are not there.
Sadly, as aviation is so safe, through years of hard work by so many, it will take many years for any problem to manifest itself. A 20-30 year ticking time bomb, which, even as an ex-cadet, I don't consider myself part of.
