Trying to fight your way out from under a noncompete, or lawyer up on account of a side consulting gig or independently conceived and developed idea, really stinks. And the further you get in your career the more likely you'll encounter such a situation.
Such cases ultimately seriously dampen both enthusiasm for the employer, and the odds of finding talent interested in working under such a regime.
Of course, the ultimate negative would be for California's exceptions to be attacked by corporate interests.
Georgia recently amended our constitution to make non-competes much more likely.
I and much of the tech scene hugely lobbied against this effort, oh well. We didn't need to work for in state companies anyhow.