Fidget spinners had been around for years, marketed as aids for kids with attention problems (a claim that has little scientific backing). But they were never particularly popular. That changed last year, after a rash of videos appeared on YouTube featuring teenagers performing fidget-spinner tricks. That caught the attention of Chinese factories, many of which have begun to employ squadrons of workers to monitor social media and Google Trends, allowing them to jump on the next big consumer-product craze as soon as it starts materializing. By the time Osborne became aware of the fad, all she had to do was go to DHgate.com, a chaotic online marketplace where overseas factories offer everything from fake eyelashes ($1.27 a pair, shipping within four days) to automobile engines (minimum order $50,000, full delivery in six weeks). There were dozens of manu­facturers offering fidget spinners in whatever quantity a buyer desired. With help from a colleague, Osborne ordered her stock from a factory where, as far as she could tell, no one spoke English, and five days later, the boxes started arriving. Soon she was selling tens of thousands of dollars’ worth of spinners each month. Her biggest competitors were gas stations and people selling from collapsible tables in a nearby park. Most of them also got their spinners through sites like DHgate.com.

For fidget spinners, as Osborne well knew, no one was going to manage the buzz, strategize about inventory and plan marketing the way Ty had for Beanie Babies. ‘‘Now, in less than half a year, spinners are done,’’ Osborne says. ‘‘I’m moving on to squishies’’ — squishable toys that are also (questionably) marketed as attention aids. ‘‘I think they’ll last at least a few months.’’

Within economics, this transition to direct selling — of cutting out sales reps like Joyce in lieu of websites like DHgate.com — is known as disintermediation, and it’s one of the defining characteristics of the internet age. Companies like Uber, Amazon and Priceline have succeeded by disintermediating enormous industries (taxi dispatchers, brick-and-mortar retailers, travel agents). The logic of disintermediation seems self-evident: By putting factories directly in contact with stores, by helping customers order directly from manufacturers, by letting riders coordinate with drivers, you cut out a needless source of waste and inefficiency. Middlemen (and middlewomen), so this theory goes, have simply been gobbling a slice of the pie they never really deserved.

In reality, though, all these middlemen were often crucial to ensuring that the pie was baked at all. As Osborne learned when she started selling Beanie Babies, middlemen like Joyce are often the ones who turn a fad into a sustainable business that creates jobs. You might think a company’s main function is to make stuff. But that’s usually wrong. Making stuff is often the easiest part of what a company does. It’s everything else — marketing and defending intellectual property, coming up with distribution strategies and knowing when to stop manufacturing Peanut the Elephant — that’s the hard part. That’s what middlemen do.

Or, at least, it’s what they did, before the digital economy made their jobs disappear. Take, for instance, the travel industry: As Youcheng Wang of the University of Central Florida notes, the industry as we know it was built, over decades, by hundreds of thousands of middlemen at travel agencies, tour operators, hotels and airline bucket shops. ‘‘There were layers of jobs and experts,’’ Wang says. ‘‘They convinced people to visit new places and helped resorts find new customers.’’ Today, however, many of those jobs and experts are gone, replaced by disintermediators like Trip­Advisor (3,000 employees) and Priceline (18,500 employees), which are built on what middlemen created, but which employ far fewer people. And the impact of losing all those jobs will have ripple effects that we can’t even predict. Who, in the absence of those middlemen, is today persuading travelers to dream bigger about their vacations, to open their wallets to support off-the-beaten-track destinations, to help new hotels find their clienteles? ‘‘Without intermediaries,’’ Wang points out, ‘‘it can be difficult to get discovered.’’

Around the same time Osborne was first hearing about fidget spinners, she visited a big toy fair in New York and stopped by the booth of Zing, a toy manufacturer that jumped on the craze early. At the fair, Zing executives were testing out an idea: What did retailers like Osborne think about a fidget spinner with LED lights that kids could program from their iPhone, so that it would spell out words as it spun?

It was a fun idea, retailers said. It could probably help fidget spinners make the transition from a fad into a sustainable product. If it worked, it would create jobs and help toy stores prosper. But Osborne and others cautioned Zing against making the investment. It would take at least six months to design and manufacture the new item, and by then, the fidget spinner craze would most likely be over. So Zing shelved the idea — and the new hiring it would have triggered.

‘‘Now a fad is just a fad,’’ Osborne says. ‘‘And that makes things harder for all of us.’’