Nobody has said don't go for the cadetship schemes.
Its the selling of the product to self financed students which is at issue. There is very little openings for them because as you have pointed out the big boys are doing cadetships now.
Unfortauntely there just isn't enough cadets to keep the current system economic its relies on a huge raft of people to fall by the wayside with destroyed dreams. I am sure you have never met the ones with debt problems and worrying about the family home being taken by the banks.