There must be a lot of junior pilots with airbus experience as well as other synergies. I converted from Boeing to Airbus fairly late on in my career and it was a very positive experience, much easier than the other way around I am told. From a passenger standpoint the cabin is much better. There will obviously be a transition period. But at some point the benefits of a single fleet will outweigh any savings from operating older aircraft. There are also substantial fuel savings to be had, so the cost of aircraft ownership is only one aspect of the total cost.