I think the biggest problem QR has is union interference. I remember reading or hearing that QR driver training takes 3 years compared to somewhere like Germany, which takes 6 months. I can't find anything to back this up though, but it sticks out in mind. It also sounds very much like something the unions would try to enforce to ensure driver scarcity and protect the financial benefits (penalty rates, overtime, etc.) accruing to the existing drivers.
RE: Dispatches #170: Moral injuries, train drivers and pain empires