History often repeats itself, particularly in relation to market bubbles. The current AI boom feels eerily familiar. Companies worldwide are pouring a staggering $6.7 trillion into data centers over the next five years. That's not normal. It's a 10-fold increase since 2022, and now accounts for nearly 2% of U.S. GDP. Railroad boom, anyone?

The stock market loves this story. The S&P 500 has surged 57% since ChatGPT launched. All-time highs. Meme stocks back in action. Investors can't get enough of the AI narrative. It's like 1929 or 2000 all over again for some AI-related valuations. But semiconductors—the actual backbone of AI—aren't keeping pace. Red flag. With 300 million jobs potentially disappearing by 2030, the market euphoria seems disconnected from economic realities.

Let's be real. AI capital spending has contributed more to recent U.S. economic growth than all consumer spending combined. That's insane. It's fundamentally private-sector stimulus propping up the economy. A few tech giants with astronomical valuations are driving this train. Microsoft talks about Azure's AI revenue, but the numbers seem... convenient.

Unlike the dot-com period, today's AI darlings actually have business models and cash flow. That's something. But investor concentration in AI stocks is concerning. Everyone's at the same party. The Nifty Fifty of the 1960s taught us how that ends.

The big question: Where's the profit? Hardware companies expect massive revenue, but who's making money from actual AI implementation? Analysts have noted that these AI data centers are fast-depreciating assets requiring constant upgrades, raising questions about long-term return on investment. The underperformance of the PHLX Semiconductor Index compared to the broader market further signals potential instability ahead. Investors were patient with the hype phase. Now they want results.

Some experts point to the railroad boom comparison. Those investments eventually paid off—after a brutal market correction. AI might follow the same path. Real value, but not at current prices.

Bottom line: AI is transforming business. That's real. But when investment reaches 2% of GDP and valuations echo historic bubbles, it's time to question if this party can continue. History doesn't always repeat, but it sure does rhyme.