Ok, I’ll bite. Having been in an airline that mixed flew 2 differing fbw Airbus types, a big one and a small one, the Regulator stopped it after one too many heavy landings so I would suggest it is not as simple as that. Apart from the obvious that the 737 and 787 are completely different and incompatible. I used to work for Thomson and these points were made. So as long as the targets are met and the bonuses come rolling in who cares eh?