Mere days after the big announcement that Square Enix are selling big studios and IPs, new information surfaced, hinting at other possible reasons why it happened.
Square Enix recently announced that they are selling Crystal Dynamics and Eidos Interactive to Embracer Group at what seemed to be a bargain price. On top of that, several legendary IPs also changed hands, including Tomb Raider, Deus Ex, Thief and Legacy of Kain.
Soon after that, reports about the company's losses with the Marvel IPs surfaced, citing a deficit of $200 million for just two games - Marvel's Avengers and Guardians of the Galaxy. Crystal Dynamics were the developers in the case of the Avengers while Eidos handled Guardians of the Galaxy. With this in mind, it looks like the studios were scapegoated among Square Enix's executives.
In any case, most gamers didn't actually consider GotG a bad game, they were merely hesitant to purchase it after the clown show Marvel's Avengers turned into. Furthermore, players were also hesitant to blame the devs for the Avengers' woes since it was clear the game's primary drive was to be a blatant cash cow even from the earliest of impressions where critics figured out there was going to be a massive amount of monetisation involved.
Following the acquisition of Eidos and Crystal Dynamics Embracer Group noted they will be looking to take over the publishing rights for both games and it's currently pending Disney's approval.