James has been bored a little over recent months and is experimenting with other sounds and techniques. I think Jake is moving forward acoustically and away from the distortion and things that Trey had him doing.
I don't think either one is envious of the other because they are playing different styles, really. Jake is such a nice guy, I doubt that he has anything against anyone. James, from what I hear, is a very nice guy and genuinely humble, too.