They’re trained that there MUST always be a recession after a decent growth period. What they’re not trained in is the effect of external political develops on creating recessions. Consider:
1a) Early 1970s - Clean Air Act, Clean Water Act, Civil Rights Act (a bit earlier, but kicking in), Arab Oil Embargo
1b) Mid to late 1970s - Economy crashes
2a) Early 1980s - Reagan-style Deregulation
2b) Mid 1980s - Economy grows like mad
3a) Early 1990 - Kinder, Gentler, America results in massively expensive updates to the Clean Air and Clean Water Acts, the Wheelchair Act, and more Civil Rights stuff
3b) 1992 - Worst economy in the last 50 years (not quite that bad, but yes, a recession)
3c) Mid 1990s - Economy left alone - grows strongly
...so now:
Late 2010’s: Massive deregulation and other pro-business policies
2020: Take a guess.
The time between 1995 and 2000 was when the first Internet boom kicked in.