To be more precise, pretty much every economist you've ever heard of agrees with this statement, which includes a couple of key caveats:
The strikingly unanimous results:
The taxi industry has argued quite the opposite: that consumers will lose out if cities open up the local transportation market to non-professional drivers who won't bother to serve low-income communities or disabled passengers.
So why do economists disagree? From the brief comments in the poll, here's Austan Goolsbee, a professor at the University of Chicago who was previously chairman of the Council of Economic Advisers (hyperlinks are mine):
yes. yes. a thousand times yes. Instead, try calling for a cab on Saturday night from the south side of Chicago and see what happens.
And his Chicago colleague Richard Thaler:
But Uber needs to be careful about surge pricing in emergencies, people care about fairness as much as efficiency.
And Oliver Hart at Harvard:
I don't see any externalities. According to standard economics, competition enhances welfare and I believe that would be true here.