It's not trivial to make an Uber clone, bit it doesn't take a 20 man developer team two years, either. The basic technology is not super complicated. You can do it with maybe five or six developers in a reasonable time frame. Most of the really interesting stuff that Uber does is scale, and you won't have to deal with that.
Source: was principal server engineer for flywheel, an Uber competitor.
That's a dumb metric. Now, let me be the first to say that Flywheel wasn't very successful in competing with Uber (and there are tons of reasons for that that I could expand upon if anyone is super interested).
But we were plenty successful in creating a system in which people who wanted to get a ride were able to hail our drivers and our drivers could come and pick up the passengers and they could cancel and see ETAs and so forth. We served hundreds of thousands of rides while I was there, and presumably more in the two years since I left.
