Cheaper? I'm seeing uncapped peak pricing making up the difference.
I am not — during peak hours the prices match those of taxis, other times they are way below. Maybe, your experience is different, but I also remember, how impossible it was to hail a cab in the situations, in which Uber today is available — even if at a higher price. What good is a nominal price of even 1 penny per trip, if you can not find an actual car?
It was so bad, economists started using the phenomenon of "umbrellas vs. taxis" as an example. Now, with Uber, Lyft at al. solving this problem, they'll have to look for some other illustration.
So, the prices really are lower throughout — comparing Uber's "uncapped" price with that of a cab is like judging Venezuela's economy by the official prices — nobody can buy anything at those either.