"Uber drivers were clearly already acting outside of the law"
Disingenuous. You'll find that most Uber drivers weren't driving illegally until Uber provided them with simple and easy to use tools for contacting customers, billing them, etcetera . It's almost like building a chemical factory and distribution network with the sole purpose of leasing said facility and service to crystal meth producers and 'distributors'. It's about as -legally and ethically- wrong as a business model can be.
Cab drivers have a higher level of driving licenses than normal drivers, a more expensive insurance policy, are subject to more frequent inspections, more health tests and harsher rules on alcohol-drugs consumption, and the cabs themselves are subject to very thorough technical inspections periodically.
In 30 years of using cabs relatively often I've only once suffered a drunk licensed taxi driver. I read in some forum several months a go a comment that stated that the commenter -a frequent Uber user- experienced that situation in Uber cars four times in the last year. Join the dots...