"Uber is profitable in certain cities, e.g. New York City [1]. They could turn cash-flow positive if they just gave up useless market share."

I would assume that would also depend on how much of their fixed costs they can shed in conjunction with that. Uber may not die quickly but it could still die slowly if they lose the ability to move forward because they had to cut too much of their R&D and sales infrastructure to get to that positive number.

Plus such a massive layoff would be a big red flag to customers too. By Uber's nature, a particular ride isn't a long-term commitment, but I think people would start looking for a stronger-looking horse even so. One of those differences between homo economus, who every time they need a ride rationally examines all their options regardless of the future and realizes that as long as Uber can complete this ride the internal state of Uber doesn't matter, and homo sapiens, who will take into account the fact that Uber doesn't seem to be doing well even if doesn't rationally matter at this particular point.