> many voters feel left behind as infrastructure crumbles, factories shutter, and coal mines close
Not sure how you’re pegging this to 2016. Coal’s been steadily in decline for 50 years — just because Trump blamed Obama doesn’t mean it’s a recent phenomenon. Same goes for factories and infrastructure—those have both been issues since Nixon was president. Let’s not pretend anything in this point is tied to 2016 in any way, other than that Trump offered empty promises that someone with any idea how the economy works would have dismissed as unrealistic.
One more thing you should add to the timeline: the British stoked Islamic nationalism in India to keep the country divided and under their control. It probably succeeded in putting off independence by about a decade, and the price for that decade was the India/Pakistan split, and a huge contributing factor to the extreme strain of Islam behind the Taliban, Al Qaeda, Islamic State, etc.