Great thoughts! I love a philosophical backdrop to the penny counting we are practising most of the day 
I hold it with @San_Francisco who in his response to @OogieBoogie mentioned some truly devastating times. Going back to the 2000 internet bubble burst or even the 1973 oil crisis does not cut it for me anymore.
There are developments that follow natural or quasi-natural laws and developments that are random or political. WW1 may have been caused by a series of random events and unfortunate alliances. The relationship of capital and GDP seems to be a quasi-law, and we are at a point where capital is mostly funneled into stock and housing market, which are mostly outside the real economy. There will have to be an event to enable further growth. Could be a war, a crash or - here come AI and clean energy again - a fundamental innovation - anything to allow capital to be converted into meaningful production.
This is not a criticism, but more a note to self: it might help to dissect topics for absolute thruths (if there is even such a thing) or natural laws and avoid comparisons. The frog in the boiling pot only ever feels a slight temperature increase, while an observer with a thermometer would have a more objective view of the real risk involved.