The day everything continued to change: an overlooked lesson of 9/11: America's strength is based on dynamism.

• Author: Welch, Matt
• Position: From the Top - World Trade Center and Pentagon Attacks on 2001 - Editorial

ON SEPTEMBER 6, 2001, the Justice Department's antitrust division dropped its three-year court battle against Microsoft. At the time, Microsoft's domestic share of the Web browser market, the proximate cause for the litigation, was around 90 percent. Ten years later, despite the government's failure to break up the company, Internet Explorer is used by less than half of the Web-browsing public.

On September 5, 2001, The New York Times described a new Kodak ad campaign emphasizing the great picture quality of high-end film. "Low-end film is a commodity," the president of the company's consumer imaging unit explained to the Times, "so we have to trade people up." The share price for Eastman Kodak, itself a two-time target of antitrust lawsuits, closed a bit more than $45 that day. Thirty-one months later the stock was down below $26, and Kodak was unceremoniously booted out of the DowJones Industrial Average after 74 years. At press time, Kodak's share price has not been north of $4 since January 2011, when the company, reeling from the disastrous consequences of trying to trade its unwilling customers up, ditched its onetime signature product, Kodachrome.

The business of America isn't necessarily business. It's change. Constant, creative, destructive, entertaining change. As we look back over the last 10 years since that awful, still-indigestible morning of September 11, 2001, it's tempting to make the counterintuitive claim that we're the same country as ever, gossiping about the sex lives of politicians, enforcing no-fly zones against Middle East dictators, tuning in to The Simpsons. Much of that is true. But on a daily basis we vastly underestimate how dynamic America is, particularly in comparison to the aims of the Islamic medievalists who turned commercial aircraft into flying death machines 10 years ago.

Regardless of whether they hate us for our freedoms or for our promiscuous, hegemonic foreign policy, jihadists, like most fundamentalists, seek to forcibly create an atavistic, unchanging idyll. Those of us fortunate enough to live in the centers of modern liberal capitalism, in contrast, embrace and create change every day, consciously or not.

When the planes hit the towers, the online encyclopedia Wikipedia was all of nine months old. Facebook (launched in 2004), YouTube (2005), and Twitter (2006) were still no more than gleams in their founders' eyes. In 2001, according to Forbes, the then-feared AOL-Time Warner was the ninth...