The capital cycle and the railroad analogy

Plain English. The capital cycle: high returns attract capital, capital builds capacity, capacity competes returns down, capital flees, and the surviving assets get cheap. The railroad analogy is its most-cited instance — the railways transformed the economy and ruined a large share of the investors who financed them. The infrastructure outlived its shareholders.

Why it moves money. The analogy reframes the AI question from whether the technology matters (the railways mattered) to who holds the depreciating assets when returns compress. Bears reach for 1929, 1987 and 2000; the standing objection is that unlike the dot-com era this buildout has enormous current revenue and binding supply constraints — customers paying now, not projected. Both can be true in sequence: real demand, then overbuild. The cycle's timing question is when capacity growth finally outruns demand growth.

What to watch. The financing transition — from surplus operating cash to debt and securitisation, historically the late-cycle marker; utilisation rates on new capacity versus contracted, speculative build; and whether revenue keeps arriving from customers rather than from other participants in the same buildout.

From the signals. The biggest infrastructure build-out since the railroad. Why the dot-com analogy keeps returning, and where it breaks. Dalio says 1929, Burry says 1987, and the argument is about definitions.