In the last 10 years, 94 percent of net new jobs have appeared outside of traditional employment. Already approximately one-third of workers, and half of young workers, participate in this alternative world of work, either as a primary or a supplementary source of income.

Internet technologies have certainly intensified this development (even though most freelancers remain offline). But services like Uber and online freelance markets like TaskRabbit were created to take advantage of an already independent work force; they are not creating it. Their technology is solving the business and consumer problems of an already insecure work world. Uber is a symptom, not a cause.

It’s worth stressing that the “technology” of temp work — and the possibility of replacing entire work forces with it — existed for years before corporations made the decision to start adopting it. Today’s smartphone app is an easy way to hire a temp, but is it really that much easier than picking up a phone was in 1950?

Indeed, shortly after World War II, a Milwaukee man named Elmer Winter founded Manpower, the first major temp agency, to supply emergency secretaries. But by the end of the ’50s, Winter had concluded that the future growth of Manpower was in replacing entire work forces. He was uniquely positioned to teach corporate America how to reduce its work forces, since nearly all of the Fortune 500 companies used his services, and he tried to do so.

But persuading companies to abandon how they operated was easier said than done, even though Winter could readily demonstrate that it would be cheaper. Few companies took him up on his offer. Higher profits were possible, but not as important, in the lingering wake of the Great Depression, as the moral compact between employer and employee.

What changed this? The emergence in the 1970s of a new, strictly financial view of corporations, a philosophy that favored stock and bond prices over production, of short-term gains over long-term investment. Theories of “lean” corporate organization became popular, especially those sold by management consultants and business gurus.

Big corporations had always had their critics, but no one before the ’70s would have thought that smaller companies would be better run than large ones. Large companies had resources, economies of scale, professional managers, lots of options. Yet terms like “small” and “efficient” and “flexible” would come to seem like synonyms. And with the rise of the lean corporation, work forces became expendable and jobs more precarious.