Suppose that you’re a middle-aged professional with a 30 year retirement time horizon. Your portfolio is 100% invested in U.S. equities–it consists of 100 shares of the S&P 500, worth $187K at current market prices.  Assuming that the fundamentals remain unchanged, which outcome would leave you wealthier at retirement: (1) for the S&P 500 to soar 200% in a glorious bubble-like melt-up, or (2) for the S&P 500 to plunge 66% in a brutal Depression-like crash?