????
We haven't gone down to pre-1990s levels, but we haven't added more debt. Private debt, by the way, is what's relevant to all these debt and credit cycles since public debt follows different rules.
edit:
Not saying that supports the argument that the debt cycle acts like a mechanical wave. The axiom that financial events have real causes (obviously they have real effects too) is pretty much always true. The problem we have now is that financial events are driven too much by corporate governance problems in the finance sector. I think Hyman Minsky's theory of financial instability is a better explanation of the business cycle than this thing. BTW, I didn't watch a video but found a
pdf by the same guy that appears about the same thing.
He's more on track than the mainstream of neoclassical macro because they hardly even admit that the financial sector exists, let alone that from it might emanate seismic waves that can liquefy the real economy. But I don't think his theory is all that useful except as a sort of vague description of how the business cycle occurs. Minsky's theory actually gives a pretty strong causal mechanism that is linked to the human world we inhabit.
Here is a link to a 1992 paper by Minsky summarizing that theory.
Notice he uses the term 'debt deflation' which I think is probably more accurate than 'deleveraging.'