GTA5 though, its a 25+ million seller. Its an industry phenominon, the likes of which can only be met by few other franchises. It even sold more than Call of Duty the year it came out. Then you have all the money the game pulls in from DLC and multiplayer DLC.
MGS5 might be a big francise, but I can understand where Konami are coming from. The business model Kojima has used for MGS is unsustainable. This is a pattern we're seeing with Square Enix, who have spent 10 years on Final Fantasy 15.
These developers have simply gone too far and the publishers are struggling to remain profitable with an unsustainable buisness model. Its understandable that they gave Kojima a deadline and a budget and he failed to meet those targets. Konami couldn't afford to support his vision anymore. I don't see them as the bad guys, they can't afford to keep going down the same road as Kojima so they had to cut him loose.