Ha. I mean, every engineer loves a green field project, and everyone wants to do a technically sweet project. But engineers of all people should understand that not every project can be technically sweet, and certainly not every project can be greenfield.
Could you imagine if everytime you wanted your HVAC upgraded, your contractor decides to rip out your entire current system and replace it with something new ("this new polymer ducting is awesome!") just to keep their engineers happy?
There's a time and a place for all types of projects, and the mark of a successful engineering effort is to have engaged engineers regardless of the 'cool factor' of their work.
In fact, this whole thing stinks of poor leadership (not just management) and undisciplined engineers.