But some may question the practices that occurs, the mentality that builds and also the difficulty in converting them to multicrew +multi systems flying. Depends on the individual I guess. But even so, is there enough to go round?
That mind-set has been going around for decades and is a myth. Recently a young CPL with 1800 hours plus and nearly all of it low level below 500 ft in a twin flying solo on survey work in the desert, completed a 737 type rating. Part of that training was as PNF to his crash-mate also doing the type rating.
Both quickly learned the duties of a first officer and their instrument and manual flying was top class. There was no "mentality" problems whatever that is supposed to mean. In other words whether or not the jet transport candidate has flown fighters, crop dusters, seaplanes or instructing, they all have to undergo the same basic type rating course on a jet simulator.
And as part of that course they automatically absorb normal multi-crew techniques. This includes briefings on the Human Factors aspects of the strong possibility in their career of crewing with a pedantic legend-in-his-own-mind, up himself captain. They are told the chances of that happening occasionally in their career is 75 percent for. In any case, any half decent airline will thoroughly brief new candidates what is expected of them as part of the Induction process.