The FTC estimates about 30 million people, or one in five American workers, from minimum wage earners to CEOs, are bound by noncompetes. It says the policy change could lead to increased wages totaling nearly $300 billion per year by encouraging people to swap jobs freely.
While they have been around forever, courts tend to take kindly to the argument that you need to be able to earn a living doing what you are an expert in, and so unless very narrow they tend to be struck down. You need a good lawyer though to get far in court which often makes the fight not worth it.
Differs from state to state. CA for instance has been shooting them down in court left and right–it’s such a guaranteed win for you that no company would actually sue you over it.
And that’s the point. It keeps lower-wage workers at bay, because a waged worker typically doesn’t have the time or resources for a long, drawn out court battle.