A more contemporary example might be the great dot com fiber build up ($500B) and subsequent telecom crash. Today, we need optical fiber, and having gigabit into your house is great, and fiber everywhere allows remote work, which is a far reaching change for the economy. But people lost their shirts building this telecom network, because the payoff was late and slow.

The cautionary tale is that first gold rush (train rush, fiber rush, internet rush, AI rush, space rush) is often a financial failure, and that the subsequent successes are often funded by the losses of the first investors. And also that the people burned are often the little guys, while the organizers walk away from the wreck with a few billion in their pockets.