So WHY is he leaving?
Good news that he is, but that he’s resigning his seat entirely and not just the Speakership requires answering _why_.
Have any modern era former Speakers retained their seats?
Because, with a possible successful challenge to his leadership looming, this frees him. There are quite a few huge matters coming before Congress (the Iran trade deal, TPP, PlannedParenthood, amnesty, etc.). If he turn-coated enough of them, he’d be voted out on the spot (especially if he tried to maintain with Dem help. He could only do that once...)
Now he has nothing to stop him from kow-towing to the wishes of the Chamber of Commerce types who want their money at the expense of America’s safety and values. He can betray us and not have to worry about backlash, because it won’t be worth the fight to get him out 3-4 weeks earlier.
Trust me, this is the calm before the storm. Things are about to get really nasty...