I don't think the fingerprinting requirements have taken effect yet. Uber and Lyft just chose to leave as soon as they lost the vote to stop them because they thought it'd give them more leverage.
They have taken effect, it's just that the city has decided to not enforce them.
City has said that it won't start enforcing until August (though technically could start enforcing as of May 1), and at that point only 50% of drivers need to be fingerprinted. Here's the original vote: http://kxan.com/2015/12/17/mayor-offers-11th-hour-compromise...