1. Greenspan's hyper-liquidity is tolerated by the global economy out of fear of what comes after the Post-Bretton Woods Dollar is finally washed up.
When major reserve currencies collapse bad stuff happens; so no one wants to go there, if possible. Hence, China etal.......currency collapse is a lose-lose propostion for everyone. China is probably quite happy knowing that someday they will "own America" lock stock and barrel.
In 1931 the Pound collapsed, and the Depression deepened....
I've always suspected that the "Great" in the Great Depression was really all about the Sterling collapse, and not the NYSE collapse.
2. Labor is weak..... So wage inflation was and is now, aborted by offshoring and other factors that keep labor fearful. That might change like it did in the 1930's, but we ain't there yet.
3. Globalism has spread out the disequilibriums(a?) --so bad things don't happen as fast as before,....that seems to be Greenspan's conculsion in the speech.
BUT, THE QUESTION OF WHY BAD THINGS HAVEN'T HAPPEN....SHOULD ALWAYS INCLUDE THE WORD---"YET."
When the "yet" happens; then it's back to the textbook models! And so-long New Era! Productivity Miracle! etc....etc.....