This post has been updated.

House Speaker Paul D. Ryan (R-Wis.) won't seek reelection, in a move that will set off a six-month scramble to find the next House speaker — or, if the GOP loses the House, minority leader.

And this should come as little surprise.

After HuffPost in December pointed to speculation Ryan would end his speakership, Politico's Tim Alberta reported that Ryan indeed had “his eyes on the exits.” And Ryan's team didn't exactly offer ironclad denials.

But even without all that, it seemed to be in the cards — if not utterly predictable.

So predictable, in fact, that The Washington Post's Paul Kane did predict it in 2015 when Ryan first became speaker. “I think he'll do this for three or four years,” Kane said in October 2015, more than three years before the 2018 election.

House Speaker Paul D. Ryan (R-Wis.) told friends and colleagues that he will not seek reelection in the ramp-up to a risky midterm election for Republicans. (Jenny Starrs/The Washington Post)

That three-plus-year tenure would be completely in line with other recent speakerships. Looking back, six of the past seven speakers have served fewer than five years in the job (three voluntarily and three because their party lost the majority). Ryan committing to another two-year Congress would put him over that five-year mark, which is a very long time to be in that job even for a relatively youthful 48-year-old.

The below chart is courtesy of Philip Bump:

And even without that history, Ryan was never going to be a lifer. He is a man who took that job, after all, even as he repeatedly insisted he didn't want it. At the time, conservatives effectively forced then-Speaker John A. Boehner (R-Ohio) out, and there didn't seem to be anybody else who could win the support of both sides of his party.

If the job was thankless for Boehner, though, Ryan was about to find out just how much more thankless it would become. Although Boehner had to deal with an unruly caucus, Ryan has found himself having to deal with an unruly and unpredictable Republican president, as well.

Frequently during the campaign and since, Ryan has been asked to answer for President Trump's conduct. While his answers are usually meant to deflect and he has outwardly declined to comment at times on Trump's comments and tweets, it is clear this is not fun for him. For a guy who built a reputation as a policy wonk more interested in being chairman of the House Ways and Means Committee than House speaker, he has found himself dealing with Trump's perpetual reality-show dramas as much as policy details.

Speaker of the House Paul Ryan (R-Wis.) told reporters March 16 that he is working closely with President Trump on health-care legislation. (Reuters)

Trump's presidency may have seemed like a golden opportunity for Ryan in one way. The GOP, after all, has joint control of Congress and the presidency, and for a guy who has long dreamed of entitlement reform and making conservative fiscal policy a reality, the chance has been there in a way Ryan couldn't have expected when he took the job in late 2015. And he did get tax cuts passed.

But Trump has already turned Senate Majority Leader Mitch McConnell (R-Ky.) into a pariah with an imperiled majority that has already shrunk by half, thanks to the Alabama special election. And given the House looks increasingly likely to go to the Democrats, Ryan can't be sure he would be able to stay speaker in 2019, even if he wanted to.

Given that, why try to stay in a job that you never really wanted and might not even exist next year?