If you squint, the AI boom in 2025 looks like a mash-up of every infrastructure mania America has ever seen. The railroad boom of the 1800s. The electrification push in the roaring 1920s. The fiber internet mania of the late 1990s.

Each era had the same three ingredients: breathless enthusiasm, an overbuilt network, and—after the crash—a foundation that quietly powered the next several decades of economic growth.

That is the irony of bubbles. They punish the wrong investors, but reward the right infrastructure. KKR's latest research makes a clean point: capital cycles come and go, but physical assets stick around and compound.

Right now, nothing is under construction faster or with more anxiety than AI data centers. McKinsey estimates that nearly $7 trillion will go into global data-center infrastructure by 2030, with more than 40% of that happening in the U.S. It is excessive, it is chaotic, yet it is also almost certainly necessary.

A Louder Déjà Vu

The late 1990s fiber buildout is the closest recent parallel. Telecom companies doubled capital spending in four years, stuffed the ground with more fiber than anyone could use, then watched the NASDAQ collapse by 78%. And yet, ...