Most recessions, busts, etc. have a "trigger". I see no trigger yet. The S & L Crisis was preceded by Lincoln S & L, Whitewater, etc. In the dotcom bubble, the trigger was fraud perpetrated by some of the big players....WorldCom, Enron, Tyco, and how about the impact of the Freddy Mac scandal when it misstated earnings and then snowballed into Bear-Sterns, AIG, Lehman Bro. exposing the risks posed by bad mortgage backed securities in the Great Recession.
Even in the 1980s oil boom, the collapse of the Penn Square Bank snowballed into the oil biz and led to the downfall of FNB of Midland, and the crisis and crash of Continental Illinois National Bank who had bet big on buying loans from Penn...
If a few such defalcations were to occur you can bet on a crash.