I’ve been kicking around in this industry for a very long time (currently on the B777). I went from TP to B737. I have to say, the TP was the most difficult thing I’ve ever flown and I didn’t find the transition to jets difficult at all. In fact, it was quite the opposite as I quickly discovered there was much less to do. If a TP guy struggles on a jet conversion it’s possible he’d 1) struggle on any conversion or 2) the training is a bit pants.