A surge in highly speculative assets may not indicate a strong economy. It can be a sign that people feel so far behind financially that they're placing huge bets, believing in an "only up" market out of desperation rather than confidence.

The rallying cry to give retail investors access to elite opportunities is not new; this same narrative fueled mass participation in the leveraged 1920s stock market bubble. Today, similar rhetoric surrounds cryptocurrency and private equity in 401(k)s, serving as a potential historical warning sign.

The current AI spending spree by tech giants is historically reminiscent of the railroad and fiber-optic bubbles. These eras saw massive, redundant capital investment based on technological promise, which ultimately led to a crash when it became clear customers weren't willing to pay for the resulting products.

The most imprudent lending decisions occur during economic booms. Widespread optimism, complacency, and fear of missing out cause investors to lower their standards and overlook risks, sowing the seeds for future failures that are only revealed in a downturn.

History shows that markets with a CAPE ratio above 30 combined with high-yield credit spreads below 3% precede periods of poor returns. This rare and dangerous combination was previously seen in 2000, 2007, and 2019, suggesting extreme caution is warranted for U.S. equities.

Widespread credit is the common accelerant in major financial crashes, from 1929's margin loans to 2008's subprime mortgages. This same leverage that fuels rapid growth is also the "match that lights the fire" for catastrophic downturns, with today's AI ecosystem showing similar signs.

The S&P 500's high concentration in 10 stocks is historically rare, seen only during the 'Nifty Fifty' and dot-com bubbles. In both prior cases, investors who bought at the peak waited 15 years to break even, highlighting the significant 'dead capital' risk in today's market.

Unlike the 2008 crisis, which was concentrated in housing and banking, today's risk is an 'everything bubble.' A decade of cheap money has simultaneously inflated stocks, real estate, crypto, and even collectibles, meaning a collapse would be far broader and more contagious.

Historical technology cycles suggest that the AI sector will almost certainly face a 'trough of disillusionment.' This occurs when massive capital expenditure fails to produce satisfactory short-term returns or adoption rates, leading to a market correction. The expert would be 'shocked' if this cycle avoided it.