Doesn't EA sports have different departments doing different sports games?
Most video game companies actually hire folks specifically to work on a game then fire them right after. I don't know how EA does it, but I wouldn't be surprised if they only kept key players around.
As for the Fight Night franchise, I haven't played it in a while, but it looked to be going in the direction of Madden in that they really had no improvements left to make. That's why they were starting to alternate with their MMA game.