Re: Run the numbers?
I'm not an expert on what is for sale on the airplane market, but I guess the whole recertification/retraining issue is a really big deal for Boeing. It's probably not just the extra costs for both Boeing and the airlines, if it's a different plane and not just a new version of an existing one the buying decision changes. Customers forced to buy a different type of plane where they must do the retraining of crew anyway will suddenly start comparing all options and may decide to switch to a different manufacturer. Once that happens Boeing has lost that customer for the foreseeable future.
It also might indicate Boeing is not capable of producing a really competitive plane and relies on the deep buy-in of it's existing customers to survive.