Questions about the financial implications of radical new technologies - AI, space travel, and their associated infrastructures, to pick a few - have led to a veritable analogy-fest. Is this a replay of the railway boom of the 1870s, which came to grief in the 1880s? A repeat of the electrification boom of the 1890s, which unfolded smoothly but took three decades to play out?

No analogy is perfect. Nor should we seek one. The most valuable insights often derive from how precedents differ from the case being considered as much as from their similarities.

In that spirit, an ...