After nearly twenty years of covering the tech world, I’ve been able to interview most of the great entrepreneurs of our time. Maybe you’d be star struck by Elon Musk or squeal at the site of Mark Zuckerberg’s hoodie. I had to throttle those feelings back when I interviewed, Julie Rice and Elizabeth Cutler in 2015.

Rice and Cutler founded SoulCycle, which is not only an urban cult-like sensation in places like New York, LA, San Francisco, Chicago and dozens of other cities, it started the boutique fitness craze.

It didn’t seem smart or obvious in 2006: To charge a whopping $30 a class, for something that was already bundled into most gym memberships. But it worked. SoulCycle did well enough, it sold almost all of its shares to Equinox, star...