Probably because he liked his situation.
From a human standpoint, he had a lot of good happening. The city (largely) loved him, he was the star player, he and his wife have lived there their whole marriage, and their child likely went to school here.
If G didn't care about winning the Cup as his top priority (which clearly it isn't since he signed with OTT), then it lines up perfectly with the story that G was ready to stay in Philly before the deadline hit & would go anywhere Fletch traded him to get more picks/players/prospects for the lineup upon his return in the summer.