Thought the article was great overall. I would nitpick the jumping off point a bit though.
The polls appear to have been wrong by around 2-2.5 points. That's actually closer than they were in the last election, and is a very typical amount of error. To ask polls to be any more accurate than this is a very tall order, and polls accurate to within 2-3 points are still extremely useful.
If someone thought this election was a lock then the error was looking at the wrong sources. It was not a failure of the system to make a reasonable prediction. 538 and the betting markets had Trump's chances in the 20-30% range. Elections don't have to get very lopsided at all to end up 90%-100% in favor of one candidate. Both sources deemed Hillary the favorite, but also clearly categorized the election as too close to call.
The felt sense (which I had) that Trump was a 'crazy, impossible' candidate and so wouldn't really win, was off.
Factual data is useful, and even biased data (e.g. polls, government-published statistics, scientific papers) are useful, and the fact that polls & Nate Silver were not hugely wrong is evidence that we don't have to throw them out entirely.