More about gyrations
Because of the fact that retirement funding is now based mostly on variable-with-stock-market-returns 401(k) type accounts instead of old-style defined-benefit pensions, when the markets crash millions and millions of senior citizens will be in trouble. It will be a crisis. The government and the Fed will step in to re-inflate the markets. Again.
All this re-inflating is serving to amplify the boom-then-bust-then-boom (then bust) cycles.