The notion that spending 5000 hrs flying GA/regional before jumping in an Airbus will be a massive advantage is completely false as the operating environments are vastly different.
Thats probably a valid observation from the jumpseat but from the LHS there is quite a significant difference. Yes cadets have good knowledge of SOPs and systems and yes the same mistakes will be made during training but the massive advantage is in the area of SA and the ability to keep ahead of the game. The operating environment when going into a CTAF is the same or worse for a jet and that's the environment your DEFO from GA/Regionals is streets ahead of the cadets. Why Jetstar are opening this up again when Flight Ops were stating that it was finishing is open to all sorts of speculation. The concept of P2F was probably a winner for HR.
Why would you not join an airline in your early 20's and earn up to $200,000 a year?
Have another read of Trevor's post.