Listened to MIB podcast today. They brought up an interesting point about Manchester United.
Man U is a global brand that is extremely valuable, so much so that the success of the brand/business could be more important than the success of the team. See the Pogba announcement on twitter for an example of timing that's fit for a global audience instead of an English one.
http://www.ibtimes.co.uk/why-did-manchester-united-confirm-paul-pogba-transfer-middle-night-1575144
I wonder if CFG has determined that Mix is no longer a draw for the team. Meaning that having Mix in the starting line-up won't raise viewership in tv or put people in the seats. Irregardless of his play he's no longer profitable for the team.
Mix's issues with NYCFC seemed to start after the Guatemala qualifier for the World Cup. Which was such a bad game for him that it basically ensured he wouldn't play for the MNT for the rest of qualifiers.
TL/DR : Mix is no longer a big player on USMNT. Mix is not going to draw in US audiences. Mix is no longer raising CFG profits.