In this chart, complaints about reckless driving spiked after the city rolled out a "How's my driving?" consumer awareness campaign in early 2012. But Wallsten's analysis also suggests rudeness and AC problems falling off.
There are two possible explanations for these patterns (and they're not mutually exclusive): The passengers most likely to complain have stopped taking cabs now that they have other options. Or cab drivers have begun to curb the behavior that causes complaints now that they have competition.
If the latter is happening, that would mean that even passengers who don't use services like Uber and Lyft are benefiting from their existence. Whatever else you think of the those companies, they have disrupted this dynamic:
In the traditional taxi world, dissatisfied consumers had few options. They could incur extra costs to avoid taxis — in terms of convenience if switching to the bus or subway or in terms of money if switching to car services or using one’s own car instead of taking cabs. Alternatively, they could complain about the poor service to the taxi regulator. Either way, taxi cabs had little incentive to improve service.