As John Campbell pointed out in a 1996 article in the journal of the Federal Reserve Bank of Boston, the landing gear of the early 1930s, before the O-ring was introduced, is an example of a “reverse salient.” That odd term has its origins in descriptions of warfare, where it refers to a section of an advancing military force that has fallen behind the rest of the front. This section is typically the point of weakness in an attack, the lagging element that prevents the rest of the force from accomplishing its mission. Until the reverse salient is corrected, an army’s progress comes to a halt.
Historian Thomas P. Hughes was the first to apply the term to the realm of technological innovation. As described in his book Networks of Power: Electrification in Western Society, 1880–1930 (Johns Hopkins University Press, 1983), a reverse salient often forms as a complex technological system advances: “As the system evolves toward a goal, some components fall behind or out of line. As a result of the reverse salient, growth of the entire enterprise is hampered, or thwarted, and thus remedial action is required.” In technological advance as in warfare, the reverse salient is the weak link that impedes progress.
Such obstacles can arise in any kind of technological system, whether its focus is a product like an airplane or a process like the management of a supply chain. Reverse salients should thus be a critical concern of managers and entrepreneurs, particularly given today’s tightly interconnected and technologically complex world of commerce. On the one hand, reverse salients present enormous business opportunities. A huge amount of economic value can get stuck in the bottlenecks that the salients form. By being the first to solve a given problem, a company can create a lucrative new market — and then grab the lion’s share of it. As Professor Hughes notes, “Outstanding inventors, engineers, and entrepreneurs usually have a record of defining and solving such problems since remedying them can unlock a vast amount of value.”
On the other hand, reverse salients also present big risks to innovative enterprises, particularly large, well-established companies. As John Northrop discovered, even a seemingly small innovation at the point of a reverse salient can quickly and dramatically alter the course of a technology, upsetting the status quo, changing customers’ needs and expectations, and turning successful products into also-rans. That danger is magnified by the fact that reverse salients can be easy to overlook. As people become accustomed to a particular product or process, they often begin to take its flaws for granted — and hence become blind to the possibility for improvement. That’s especially true of people who had a hand in creating a prevailing system and thus have a direct stake in its perpetuation.
Even Thomas Edison, the greatest American inventor of all, fell victim to this affliction. When, in the late 19th century, he pioneered the utility system for distributing electric power, he came up with brilliant solutions to a series of reverse salients that were hindering the design of lightbulbs, wiring systems, generators, and so on. But he became so enamored of his own system that he didn’t realize that one of its core technologies — direct current — was itself a reverse salient. Because direct current could only be transported short distances over wires, it set a limit on the size and scale of early utility plants and prevented the next technological leap in power distribution. When Nikola Tesla invented motors that could run on alternating current, which had no such transport limits, he broke through the reverse salient at the heart of Edison’s system. Edison’s archrival, George Westinghouse, quickly bought Tesla’s patents and used them to construct the alternating-current grid that, to Edison’s dismay, became the dominant electricity distribution system.