It could be part of a bigger plan to get them sold off to Jet2, Ryanair or Thomson. Nobody wanted to buy them as an Airbus operator, perhaps they think they have a better chance as a Boeing operator. We all know it's not about the long term profitability of the airline that is a priority. It's a buying the airline on the cheap and trying to flip it as quickly as possible for the maximum price.
When you think of it all you'll need is the deposit for the aircraft. The mortgages will just be an ongoing business expense. Boeing will chuck free training into the bargain and there you go like Airbus did when EasyJet went Airbus.