The NYT had a piece today on the Initial Public Offering (IPO) of Uber and other recent start-ups. It notes that this generation of tech start-ups has waited much longer than the start-ups of the dot-com era to go public. The piece tells readers that this longer period gives:

"start-ups have had more runway to figure out sustainable business models while avoiding the public eye."

The problem with this assertion is that start-ups like Uber and Lyft don't seem to have developed a sustainable business model. In Uber's case it is losing billions of dollars a year, even as it is likely to face higher costs going forward due to efforts at various governmental levels requiring it to obey labor laws. It seems investors are still prepared to pay billions for these companies, but that seems to have little connection to whether they have a sustainable business model.