That doesn't seem to be a problem for the competition. Prices are the problem, and Uber is trying really hard to lower the prices and profit, that's why the algorithm IS most important.
I really do not understand why almost everyone thinks that "network effect" is the best thing Uber has, when it obviously isn't.
I really do not understand why almost everyone thinks that "network effect" is the best thing Uber has, when it obviously isn't.