Is "Wile E. Coyote moment" mainly an economic metaphor?

The person usually credited with making the connection between Wile E. Coyote with economic disaster is the U.S. economist and New York Times editorial writer Paul Krugman. From an unidentified article in the National Journal Journal, volume 36 (2004) [combined snippets]:

In an October [14,] 2003 column, "Don't Look Down," Krugman said that, unless properly managed, the devaluation of the dollar could lead to a "Wile E. Coyote moment" when the world realizes that the U.S. economy has been levitating on an overvalued currency.

From an unidentified article in Market Intelligence (2004) [combined snippets]:

The Kenya economy's slow emergence from a recession, which has to be backed by credible public sector reform, will be desirable to quick fixed buttressed by unrealistic expectations driven by uninformed commentary. The latter will at some point lead us to a Wile E. Coyote moment. For those "serious minds" that may not be familiar with the Road Runner cartoon (another cartoon!) Mr. Coyote has this habit of running off cliffs and taking several steps on thin air before noticing there is nothing underneath his feet. Then he surely plunges, as the economy could.

And from an unidentified article in The Bulletin (December 12, 2006) [combined snippets]:

Then came what Princeton economist Paul Krugman calls the Wile E. Coyote moment.

(For those not familiar with the classic Warner Bros. animated shorts, Krugman says there were often scenes in Road Runner cartoons in which the ever-frustrated Wile E. Coyote would run off a cliff, take several steps in thin air, then look down — and only after realising that there was nothing under him would he plunge.

Following up on this usage somewhat belatedly (but just in time for the Great Recession) is an unidentified article The Economist (2008) [snippet view]:

In America a tax rebate landed in people's bank accounts in May and acted like a ose of smelling salts on a groggy bruiser. Although Merrill Lynch estimates that some 90% of the rebate was saved, there was still enough money around to boost sales of food and electronics. In Britain consumers may have experienced a Wile E. Coyote moment: having walked off the edge of the cliff, they have only just looked down.

Other instances of "the Wile E. Coyote moment" in the context of economics are detailed in Milind Lele, Monopoly Rules: How to Find, Capture and Control the World's Most Lucrative Markets in Any Business (2005), in John Katz & Frank Holmes, The Goldwatcher: Demystifying Gold Investing (2008), in Eric Helleiner & Jonathan Kieshner, The Future of the Dollar (2009), in Dean Starkman, Martha Hamilton & Ryan Chittum, The Best Business Writing 2013 (2013), Jonathan Kirshner, American Power After the Financial Crisis (2014), and in Charles Wyplosz, Thirty Years of Economic Policy: Inspiration for Debate (2015).

Many of these later publications cite Krugman as the originator of the phrase. But there is evidence that the expression first appeared—in a non-economics setting—ten years before Krugman used it. From Last Action Hero: The Official Moviebook (1993) [combined snippets]:

Results are disappointing. Several reasons are cited. "If we dropped like that, our faces would vibrate in the intense wind," explains Neal Nordlinger. "But Arnold [Schwarzenegger] has no body fat. You can't tell that he's falling." It is also obvious that the rig is physically restricting—Arnold's arms keep running into his cables. And lastly, the fall is too fast. There's no time to react. By the time Arnold has started his "Wile E. Coyote moment," the breaks have started to decelerate. Perhaps additional height is the solution. A new rig is built and Arnold is asked to try again.

Another early instance of the expression appears in what seems to be an economic context. From an unidentified article in Time magazine, volume 155 (2000) [combined snippets]:

Yeah. The wold ended. The fact that the NASDAQ may have hit a new high by the time you read these words doesn't erase the vague sense in dotcomland that the party, if not quite over, is definitely winding down. It's behemoths like Cisco and Intel that are keeping the NASDAQ afloat. The Web bubble is bursting. Has burst. Which means that some of us now roaring toward online glory may instead face that Wile E. Coyote moment when you look down and realize you just sprinted off a cliff.

At my firm, of course, we're fine. Those jerks down the block may obsess about IPO millions but here at Keen.com we care only about building a great business by continually improving our products and better serving our customers' needs ...

Although the expression has, thanks to Krugman, achieved special status in economic writing, it has continued to appear in non-economic writing as well. For example, authors allude to it in Mythprint, volumes 40–41 (2003), in a review of one of the Lord of the Rings movies; in Sharai Erima, Passing Solidarity: One Man's Search for Identity in a Global Context (2005), a memoir; in Chris Wood, Dry Spring: The Coming Water Crisis of North America (2008), a doomsday science exposé; in Philip Graham, The Moon, Come to Earth: Dispatches from Lisbon (2009), a biography; in Luke Reynolds, Jennifer Reynolds & George Saunders, Dedicated to the People of Darfur: Writings on Fear, Risk, and Hope (2009), a reminiscence; in Matthew Hiley, Hubris Falls (2010), a novel; in Brother Tom, The Angel and the Rowboat (2013), another novel; and in Scott Stossel, My Age of Anxiety: Fear, Hope, Dread, and the Search for Peace of Mind (2014), another memoir.

Conclusion

The upshot of these Google Books matches is that the expression "Wile E. Coyote moment" goes back at least to 1993, when it appeared in a "moviebook" about an Arnold Schwarzenegger vehicle; that it appeared in an economic context at least as early as 2000; that the probable source of its current popularity in economic settings is an editorial/essay by Paul Krugman from 2003; and that, although the expression continues to be quite popular in the context of economics, it also appears with some regularity in non-economic settings.

In his autobiography, "Chuck Amuck: The Life and Times of an Animated Cartoonist," the cartoon's creator described nine rules he followed when creating each RoadRunner episode. Rule #8 said that whenever possible, gravity should be the coyote's enemy.

The coyote never considered gravity to be a threat. It wasn't until he slid off a cliff with nothing beneath him that he realized the danger. At that instant, he paused in mid-air, his facial expression changed and he began his plummet downward.

A Wile E. Coyote moment refers to a time when you suddenly realize that something you never considered to be a threat is going to severely harm you. Using it to refer to the national debt and the economy is one use, but it applies universally.

Perhaps it's encouraging for the economy that Rule #9 says the coyote must always be more humiliated than harmed!