I agree that Uber is using VC cash to outcompete more effective businesses. It's not sustainable, but in many cases those businesses were predatory either to their employees or the public. This isn't the case everywhere.

I talked with some ex-cabbie Uber drivers. With cabs, they had to pay back the owner each shift for use of the vehicle and license. About half of the shift would be worked free. If they were new and got weekday graveyard, it was particularly bad. They seemed much happier with Uber. I'm a bit concerned about hard to quantify costs like vehicle wear ultimately making it worse, though.