“Technologies want to survive, and they reinvent themselves to go on.” (Paul Saffo, technology forecaster in Silicon Valley.)

Technology expert Steve Lohr, writing in yesterday’s New York Times, shares a fascinating theory centered around the fact that, contrary to popular opinion of recent years, many of yesterday’s technologies aren’t dead yet; they’re alive, kicking, and often still turning a profit for their respective manufacturers.

To prove this theory, Lohr explores the state of the mainframe, I.B.M.’s classic contribution to technological hardware. The company released a new version of the mainframe last month; remarkable, given that the equipment was famously predicted to be put out of its misery by 1996. The author then uses this example to shed light on history’s other obsolete technologies that just never went away.

Today, mainframe sales are a tiny fraction of the personal computer market. But with the mainframe facing extinction, I.B.M. retooled the technology, cut prices and revamped its strategy. A result is that mainframe technology — hardware, software and services — remains a large and lucrative business for I.B.M., and mainframes are still the back-office engines behind the world’s financial markets and much of global commerce.

The mainframe stands as a telling case in the larger story of survivor technologies and markets. The demise of the old technology is confidently predicted, and indeed it may lose ground to the insurgent, as mainframes did to the personal computer. But the old technology or business often finds a sustainable, profitable life. Television, for example, was supposed to kill radio, and movies, for that matter. Cars, trucks and planes spelled the death of railways. A current death-knell forecast is that the Web will kill print media.

What are the common traits of survivor technologies? First, it seems, there is a core technology requirement: there must be some enduring advantage in the old technology that is not entirely supplanted by the new. But beyond that, it is the business decisions that matter most: investing to retool the traditional technology, adopting a new business model and nurturing a support network of loyal customers, industry partners and skilled workers.

The unfulfilled predictions of demise, experts say, tend to overestimate the importance of pure technical innovation and underestimate the role of business judgment. “The rise and fall of technologies is mainly about business and not technological determinism,” said Richard S. Tedlow, a business historian at the Harvard Business School.

To survive, technologies must evolve, much as animal species do in nature. Indeed, John Steele Gordon, a business historian and author, observes that there are striking similarities in the evolutionary process of markets and biological ecosystems. Dinosaurs, he notes, may be long gone, victims of a change in climate that better suited mammals. But smaller reptiles evolved and survived, and today there are more than 8,000 species of reptiles, mainly lizards and snakes, compared with about 5,400 species of mammals.

It’s a fascinating article; click here to read it in its entirety. And, as always, let us know your thoughts in the comments section.