Because the rules for cab companies actually serve a purpose--they actually ensure that there is some minimum level of service that the consumer can count on in terms of service, fares, non-discrimination, insurance liability, etc.
If services like Uber and Lyft simply decided to be a cab company with excellent technological underpinnings, people would have been quite happy with them and they would have been quite profitable. And they could have blown most cab companies out of the water. Buying up inefficient operators, consolidating them, and bringing them into the modern world of technology is a really good business plan.
Uber and Lyft are in trouble because they wanted to be exit strategy profitable rather than simply profitable. And they decided to do this by ignoring all of that icky stuff like liability insurance, commercial licensing, and following the law. In addition, Uber and Lyft tend to want to ply their trade in areas which are already profitable to cab companies rather than taking over areas that are underserved. If they were brokering rides in areas that can't get cabs easily, they would have lots of defenders.
There is a big difference between laws that actually protect consumers vs. laws that protect middlemen. The fact that pg can't see the difference is a pretty big issue.