You’d be surprised. Californians love their ability to Uber, if this gets rid of that (or severely curtails it), they would have no problem overriding the legislature at the ballot box.
If this law is applied fairly, it affects taxi and limo operators as well, so everyone will be in the same boat at least, fares will surge but they will still be in business.
[1] https://investor.uber.com/news-events/news/press-release-det...
Many of those people are already employees or owner/operators. That's why Uber, etc. was able to undercut their fare rates.