Motorola has one tablet... Asus has 4-5 tablets... I doubt they focus resources on updating our beloved T1. My wife's t1 a bit slow, dunno if it could handle the requirements of jb.
The Xoom will be staying at 4.1.2 I believe, no promises. As for the 101, ASUS already confirmed there are no plans for Jellybean. However, the developer community will probably support it for as long as humanly possible.