Cisco's stock took 25 years to reclaim its year-2000 peak, despite the underlying business growing significantly. This serves as a stark reminder that even a successful, growing company can deliver zero returns for decades if an investor buys in at an extremely high, bubble-era valuation.

The Shiller P/E ratio, a measure of long-term market valuation, has only crossed 40 three times: 1929, 1999, and today. The first two instances preceded major market crashes (The Great Depression, Dot-com Bust) and were followed by a decade or more of flat or negative real returns for investors.

The concept of "Nihonjuron," the theory of Japanese uniqueness, was used to rationalize extreme asset valuations that defied Western financial logic. This cultural narrative created a national blind spot, allowing investors to believe that traditional fundamentals didn't apply to Japan's seemingly superior economic system.

Historical data shows no exceptions to the rule that an asset class reaching a two-standard-deviation (two sigma) valuation above its long-term trend will eventually return to that trend. This statistical certainty applies to stocks, bonds, commodities, and currencies, making severe drawdowns from such peaks inevitable.

With the S&P 500's Price-to-Earnings ratio near 28 (almost double the historic average) and the Shiller P/E near 40, the stock market is priced for perfection. These high valuation levels have historically only been seen right before major market corrections, suggesting a very thin safety net for investors.

A rare but reliable historical indicator of a market peak is when speculative, high-flying stocks begin to decline even as the broader blue-chip market continues to climb. This divergence, seen in 1929, 1972, 2000, and 2021, signals a late-stage rotation to perceived safety just before a major downturn.

When an asset sees a massive price surge, it's effectively a "price compression" that pulls years of expected returns into a short period. This raises the probability of future volatility or stagnant performance, as the future gains have already been realized.

The CAPE ratio, which compares stock prices to average 10-year earnings, is at a level seen only twice before in history: just before the 1929 Great Depression and the 1999 dot-com bubble. This indicates a severely overvalued market ripe for a major correction.

During the "Go-Go Years," even premier companies like Disney and McDonald's traded at over 70x earnings. While the businesses survived and thrived, investors who bought at these peaks faced years of poor returns, proving that a great company can be a terrible investment if the price is too high.