It's true.............dead easy to train a cadet to fly an A320 say, then when they are out on line, they 'toe' the line so to speak.
Conversely an ex 737 jockey from another airline, might find the transition a little more difficult. Not because they can't hack the course, but the major problem is un-learning the old type and the 'old company' SOP's. How often do we hear, "we never did it that way in my previous outfit" The impression often given is the way they did it before was better ! Then when out on line there is a tendency to 'drift' back to what they've been doing for the last 'x' years.
A generalisation I know, but may go some way to an insight into some companies thinking and recruitment policy.