Before the 1928 crash and subsequent regulation as well as going off the gold standard, instituting the Fed, and other things, the ups and downs were insane in both socks and inflation.
See the massive fluctuations in inflation as well as the DJIA? After the New Deal and other reforms, we not only hit post WWII American growth but a relatively stable upward trend in the markets and policy with targets like stable economic growth and more recently stable inflation (currently I think a 2% target).
Regulation and restrictions plus Fed oversight has granted our modern economy relatively stable year over year growth and inflation. Stability means future predictions become ore accurate, economic panics/recessions can be not necessarily predicted but solutions approached strategically.
Deregulation and instability can make people insanely rich similar to the hyper leveraging of this whole RH thing but one usually has to either be the know like via have insider information or be prepared to tank everything for their own arrogance like when some guys tried to corner the gold market in 1869 (Black Friday) or the onion market in the 1950's: https://en.wikipedia.org/wiki/Cornering_the_market
