It's very easy to forget that the revolutions of Britain, France, America, Russia; it happened just a few generations ago, and upended most of the political landscape (even in countries that didn't see actual revolutions). I think what is happening is most of our modern institutions are all of roughly the same age, and after initial idealism and momentum have roughly at the same time begun to ossify and show cracks as people have started taking them for granted.
This is the first time anyone has attempted democracy on this sort of scale. Looking back we've had republics with longevity, we've had autocratic dynasties with longevity. But democracy? Besides Athens, which had a very different shape of political system, this is really a first. It's a huge political experiment, the long-term viability of which is being determined here and now by our ability to keep our shit together.