The revolving door at the top of Silicon Valley companies has ushered in a lot of familiar faces lately.

In April, Zynga founder Mark Pincus, who had left the CEO job in 2013, returned to the helm at the online game company. Then in June, Twitter named co-founder Jack Dorsey as its interim CEO while it searched for a new leader to guide the social media platform. And on July 10, Reddit replaced its interim CEO Ellen Pao, after she resigned amid widespread user criticism, with one of the online discussion forum's co-founders, Steve Huffman.

None of these were quite the triumphant return of the king. Zynga's stock sank 18 percent the day after Pincus announced his return, with one analyst saying the move was "unlikely to reassure" either investors or employees. Dorsey's return as Twitter chief executive is likely short-lived, as he is also CEO of the company Square and the board has said it wants its CEO to commit full-time to Twitter. Meanwhile, Huffman's initial policy proposals for taming the hate on Reddit were met with some criticism.

So why the apparent love affair with Silicon Valley's founders? The answer is simple, says Steve Mader, managing director of board and CEO services for the executive search firm Korn Ferry. "It is speed," he says. "In tech, you can die so fast."

The founder, in some cases, has enough equity to make a strong case for returning. He or she also, in theory, is well-known to the board, understands the ins and outs of the company's issues, and has the moral authority to move in and make big changes quickly."Re-entering founders have no learning curve and [can] re-ground the business in its purpose most quickly," Mader says, "not always as professional managers but as leaders, which buys time that could otherwise be fatal."

The re-anointing of Pincus, Dorsey and Huffman may represent nothing more than a random blip in Silicon Valley's long-running romance with reinstating its founders. (Think Steve Jobs, Michael Dell, Larry Page, Jerry Yang.) While there are a few high-profile examples from other industries—Howard Schultz at Starbucks, for instance, or Charles Schwab at his eponymous brokerage—they are much more common among fast-moving tech companies, particularly ones facing turbulence, Mader says.

Jeff Pfeffer, a professor at Stanford's Graduate School of Business, says he doesn't think there is necessarily an increase in the popularity of tech companies turning back to founders, but high valuations and ever greater expectations for growing Silicon Valley companies could be contributing to more tumult at the top.

Boards of companies that are facing difficulties typically have two choices, Pfeffer says: Choose someone from the inside—a fraught decision when a company is struggling—or bring back a leader who has a relationship with the company to serve in the role temporarily. "Outside searches are risky and take a very long time," he says.

Others say we could also be seeing some shift in the perspective of tech company boards. Sydney Finkelstein, a professor at Dartmouth's Tuck School of Business, says there's less enchantment with established executives from big outside companies than there was in the Internet's first heyday. "Many of them didn’t do well. They didn’t have their entourage and their team with them," Finkelstein says. "There's a bit more of a recognition that having a professional manager is not automatically going to solve all your problems." 

Meanwhile, influential venture capitalist Ben Horowitz has made the case for founder-CEOs in a blog post that has been widely shared. "Often, true innovation requires throwing out many of the foundational assumptions of the company," he wrote. "If the company is significant, doing so may be extremely difficult for the professional CEO."

From shows featuring Silicon Valley entrepreneurs to the cultural fascination with all things Apple, there seems to be an increasing reverence for tech entrepreneurs—a reverence that may also be influencing tech company boards. "As a society we've elevated the startup CEO to a place where we used to place the titans of business before," Finkelstein says.

Chief among those icons of Silicon Valley, of course, is Apple's Steve Jobs, who pulled off the founder-CEO second act in unparalleled fashion. It's not lost on Stanford's Pfeffer that the mythology surrounding Jobs' success could be prompting some founders to aim for their own second shot at the top, whether advisable or not. In Silicon Valley, Pfeffer says, "there is not a shortage of ego."

Read also:

Like On Leadership? Follow us on Facebook and Twitter, and subscribe to our podcast on iTunes.