"It's like what happens in Hollywood: You have tens of thousands of young people flocking to Hollywood thinking that they're gonna become a Brad Pitt or an Angelina Jolie; they don't," said Wadhwa.
"They don't become billionaires. There haven't been many Mark Zuckerbergs after Mark Zuckerberg achieved success."
And Wadhwa says there is little evidence the Thiel dropouts are doing much that isn't already being done in Silicon Valley."Everyone does the same thing: It's social media, it's photo sharing apps. Today it's sharing economy," Wadhwa said. "It's 'Me, too,' 'More of the same.'"
But 19-year-old Conrad Kramer and 21-year-old Ari Weinstein were convinced they had a new idea, so when they were awarded Thiel Fellowships in 2014, they both walked away from MIT to work full-time on their app, called Workflow.
"There are some opportunities that come up that you would regret turning down," Kramer said. "Workflow was definitely one of those."
"It's kind of like making your own apps that save you time," Weinstein said.
When Workflow launched, it was the number one bestseller on Apple's App Store -- and has since won several awards.
They've just hired their newest employee, Tim Hsia, a graduate of Stanford's business and law schools and an Army vet. He's 33-years-old and says he doesn't mind taking orders from a teenage boss.
"I'm learning so much because they have such a wealth of experience despite their age," Hsia said. "In Silicon Valley it's about meritocracy of ideas. And so if you have a good idea, everyone's always receptive to listen to it."
Zach Latta found many people were willing to listen -- leaving high school to move to San Francisco on his own, to start a non-profit called Hack Club.
He recalled that when he moved to the city at age 16, "I'd showed up at a gym one day with some friends, and they turned me away at the door because I had to be 18."
Now he is 18 and works full-time helping high school students learn to code.
"I feel challenged in every single day," Latta said. "And I think I'm learning as much as I've ever been while being happy."
For now these wannabe tech titans live modestly in homes they share with several others, or in offices that also provide a place to sleep. Instead of meals, some drink Soylent -- Silicon Valley's version of fast food. It apparently contains all the nutrients necessary to stay alive, in a bottle.
"Yeah -- breakfast, lunch, snack, dinner," said Latta.
They are building their companies with money from investors who seem to care little whether they graduated from college.
"It's actually kind of a badge of honor here, dropping out," said 23-year-old Stacey Ferreira. She's dropped out of NYU -- twice! The first time she saw a tweet from Richard Branson, the founder of the Virgin Group, offering to meet anyone who gave $2,000 to his charity.
She borrowed the money and met him. She was 18 and starting her first business.