https://duckduckgo.com/?t=ffab&q=uber+did+not+show+up&ia=web would suggest there are people who ordered an Uber ride that never showed up.
Uber says it's possible for a ride to not show up: https://help.uber.com/riders/article/i-would-like-to-get-a-r...
Uber even says it's possible for someone else to take the trip you requested, without your knowledge. https://help.uber.com/riders/article/i-was-charged-for-a-rid...
Ah, that's a good one actually. So, with Uber is there any certainty? Do they give you money back or something if the Uber doesn't appear on the specified time?
It has happened to me that I have waited a bit over the usual time for my taxi, but not very often.
I needed a ride from queens to NJ and many cab companies simply hung up on me.
I dislike uber the company but cabs were worse, for me.