He definitely is bitter and has been obvious for a while now. I think Henry's ego thought he would make a great manager and probably saw himself as the heir to Wenger. He also aligned himself with the Spotify guy and wanted to take over Arsenal, maybe he saw that as his route into the club. Those of us who have been following long enough know there is a bitter side to Henry, look at his treatment of Jose Reyes for proof. He manages his PR carefully but deep down there is a bitter twisted side to him.
Bottom line is the club was a mess from top to bottom and needed a strong character to lead on and off the pitch. Arteta was fortunate that Raul was gone and he worked with Edu and the upper management to turn things around in a way that none of us thought was possible. Even when things looked shit from our point of view you felt within the club they could see Arteta was turning things around and he fully earned the trust of the Kroenke's. We've gone from a laughing stock to one of the reference clubs in Europe, everyone is trying to model themselves on us now.
Emery is a good coach but that is it, Arteta is literally the face of the entire club. Emery needs a strong director of football with him and is only interesting in coaching the players, nothing else. When Emery came here he could not deal with the other side and could not deal with the difficult characters in the dressing room, Arteta came in and with the support of the club got rid of all the bad apples.