The day they do pop, there is no further warning. News comes out, and the market reacts billions of microseconds before retail learns about it, an eternity.
> The dot com bubble took about 9 months, iirc
It took 39 months and 5 days from Fed Chair Alan Greenspan’s “irrational exuberance" description (1996-12-05) until the bubble popped (NASDAQ market peak on 2000-03-10). Greenspan wasn’t the first critic, either, though he was obviously a very high profile one.
Just my own observations and memory.
A number of government policies adopted before the bubble burst under Clinton and before the bubble bursting had worked its way into the public consciousness under Bush (safett net cutbacks, downward tax burden shifts, etc.) made the November 2001-December 2007 aggregate expansion after the 2001 recession and before the Great Recession have very poor distributional characteristics, such that much of it, especially the first couple years, felt like a recession for most outside of a narrow elite, which probably combines with the emotional impact of 9/11 to fix that late date as the beginning of the downturn, even though it was near the end of the downturn in aggregate economic terms.
edit: and again, I'm in Phoenix so well outside CA/WA, etc...
My guess as to what happens here is one of the big players showing that they're cutting back on capacity in a significant manner, which will spook the investors who know a bubble pop is coming but want to time their exit as near the top as possible. By the time the pebbles notice, the avalanche will be in full roll.
The question we have to ask is - what event will trigger this? To the extent that marginal investors (who who are price makers) will seek to exit.