Nothing is Obsolete as long as it still works and does the job.
My thought was that the tighter choked 31's are not made for steel shot.
The only thing we shoot steel at around here is waterfowl.
Upland birds, turkeys, rabbits, squirrels, etc still get lead and if you wanted to shoot ducks with the 31 a box of heavyshot isn't out of the question.
