The cost isn't surprising. Metal Gear is one of those series with expensive production requirements, and it's been long assumed Kojima and co are sticklers for quality/vision so much so that shit gets delayed and changed routinely. It would be nice to live in a world where money was no object, but it is, and I can see why studio executives and producers would be very frustrated with what to them seems like a lot of money burned on mismanagement, lack of vision, oversights, etc. Keep in mind numerous games from other studios have been pushed out early, scrapped, or moved over to entirely new teams for the exact same situation as we're hearing with Kojima Productions. And KojiPro is the kind of studio that burns out money on failed Rising builds. As Konami shifts towards aggressive, quick profitability (eg: mobile and F2P market) this kind of development process is seen as a massive waste of money and resources. If they don't feel that model is sustainable for their future, irrespective of how we feel, then so be it.
That being said, absolutely nothing excuses the abysmal treatment of employees. It sounds like after a long time a perceived waste of money from KojiPro the last delay of Phantom Pain was the nail in the coffin. Board flipped, crunched down on all staff and introduced absurd policies that would permit them observation and control of employee hours. They just want the game finished.