Was told that the Q400 would initially out climb the Fokker so fortybelow has a point.
PX certainly had too many types, DH8 classics, DH8 400's, Fokker, B737, B767, so with all the required spares, maintenance and training must have been a killer expenditure wise, so the idea of reducing types was a smart move.
However PX airframes have become LG (last generation, with the noted exception of the 737NG).