On March 13, 2020, Glenn Kelman, the chief executive of the online real estate broker Redfin, was biking to work when he got a call from Henry Ellenbogen, a longtime investor in Redfin who had started his own fund.At Harvard, Mr. Ellenbogen majored in the history of technology. One big thing he learned, he has said, was that technology is developed well in advance of people’s ability and willingness to use it.“Tell me something,” Mr. Ellenbogen asked Mr. Kelman, according to an account the chief executive posted on Redfin’s website. “When people start touring homes via an iPhone, …
