As a driver who's lived in SF for a long time I've seen first hand the terrible impact these services have had to the city. They clog streets and disregard any and all traffic laws. Just yesterday an Uber driver made a left turn from the middle lane on Hyde street. He backed up traffic as he refused to move until someone let him make his illegal turn. He was the recipient of a lot of honks.
His response? Gave everyone the finger after he finally made his left hand turn. Lovely. He should lose his license, period. In the days before these services existed cab drivers were petrified of getting in trouble. Many Uber/Lyft drivers are modern day lawless pirates.
A modern medallion system driven by traffic/ridership data with as little chance for corruption as possible would be the best answer to these problems. Uber/Lyft as they exist today cannot be allowed to continue if we value quality of life/safety.