The title, is after all, the only plausible explanation for the wonderful glorious trash that is 1709. We don't actually have a source, but we are confident in our assertion that someone, somewhere, within Microsoft said something along the lines of "Oh man, 1607 was so bad, I bet a team of monkeys could do better!" and the answer was a not totally unexpected "BRILLIANT!"
and many more.
There's the USB drivers issues. Some Lenovo's that take the update wrong end up with a borked USB root hub, which is made better by the fact that the laptop keyboard actually goes through the thing. How does one even troubleshoot without a keyboard? The blue screens. Oh, the Blue Screens. So many, so many variants, and not all of them even solvable without resorting to insane amounts of wasted time. Then of course there's the epic fact that some of Microsoft's own Surface line crash with the update. Wonderful.