Sean Behr, the chief executive of the parking service Zirx, epitomizes the change. The company, named after the Ukrainian word for star, was in the “on-demand” space, providing valet parking with the touch of a smartphone button... But each customer was so expensive to acquire and serve that Zirx lost money and consumers in all six cities where it operated. By late last year, Zirx, a San Francisco start-up that had raised $36 million, had only about a year’s worth of cash left. So in January, Mr. Behr... told customers Zirx was shutting down its on-demand businesses where valets would park cars for any customer who asked and would instead focus on more lucrative corporate clients.

http://www.nytimes.com/2016/08/29/technology/warned-of-a-crash-start-ups-narrowed-their-focus.html