It's widely known state of things because of the current situation (low interest rates for very long time, etc.). Infact, many financial institutions and experts have been of the idea that a major stock crisis was around the corner for a while.

You could argue that most would have disagreed, but at the end 2018 many stock crisis indicators, models and statistics started to turn red and indicate that a crash was close.

2019 had a couple of close calls like the Turkish lira crisis, but there was never widespread panic to feed a worldwide crash. Now there is.