Could they make special simulators to provide that training?
They would probably very big and expensive, and espectacular, but crews would only need to use them for an initial training and then once every few years for refreshing.
They could build them multi-type, with a cockpit that could be quickly switched from a boeing 777 to an airbus 320 in half an hour. The cockpit would be mock up, anyway, except for the flight instruments and the flight controls and thrust levers. Size could be reduced by making it single seat, or double but with the instructor seating in the cockpit and having the sim controls in front.
It would be nice. Manufacturers would love the idea, too.
Then add some politicians...