Found this piece in which Lyft boasts that they had more driver upon coming back to Austin, and where RideAustin states that their numbers have dropped from 50k weekly rides to 20k rides, which is their minimum number to remain relevant.

Drivers probably signed up again with Lyft/Uber simply because these apps had again a significant volume of business to offer.

Also, I saw on reddit that RideAustin had closed its onboarding office, which seems like the best way to send drivers to their competitors.

http://austin.culturemap.com/news/innovation/07-27-17-ride-s...

Because thats where the passengers were. (In both cases)