I feel like the charts below demonstrate, quite well, the boom / bust cycles created by fiscal and monetary policy in the United States (and elsewhere).
These generated cycles allow large investment banks to make mucho fiat.. "Banks" like J P Morgan Chase, Goldman Sachs, Bank of America, Wells Fargo, Citigroup, so on so forth.. (here is a list of large banks I found)
These banks, with the complicit assistance of the Federal Reserve Bank, have used these boom / bust cycles to generate predictable profits for decades, game the system, if you will, as *I* think these charts clearly indicate.
In my humble opinion we are currently in a bust cycle and it appears, to me, to have further to go before it completes.
In part the big banks / FED depend on YOU being on the wrong side of the trade.. Don't do it anymore..
SPX 20 year / monthly candles
Alternative view (SPY)