OK, I can try and steel man it for you. Warning, long.

California hasn't had noncompetes for a long time (B&P 16600). But if you look in the code right around there, there are a few carveouts that cover most of the situations that are used most of the time for legitimate cases, like the split up of a closely held company.

There are other extreme examples that use a slightly different legal theory, like professional athlete contracts, which also rely on the forbearance of the other teams from employing the person in that specific role, though if Lebron wanted to pour beers for the Knicks, I'm doubtful that's covered. (Back when they were the worst team in existence, I did some work for the Warriors.)

The real reason they're haven't been so many issues in California is because they make you sign all kinds of things about IP, trade secrets, and so on which they will always start with if they really want to block a move. The courts know the score, they know this is just non-compete by other means, but if you cover your bases, it usually works (i.e. move is ok). Your new employer knows the score too and will usually just work a deal or fight the case. But if the cost gets too high, or maybe you kept an email print out you shouldn't have, it can get gnarly/expensive. And even just that drag/delay is enough of a deterrent.

So what's left? An employee who leaves with no critical information who just wants to open a competitor near by? There are a few circumstances like this where it might matter. Small company, key employee leaves, he has no IP, but it will probably impact your business. So what do you do?

Realistically, you probably engage in guerrilla tactics. And this brings me to my steel man.

How much of the oblique, bank-shot BS litigation (the guerrilla tactics I mentioned) about "trade secrets" is really just back door non-compete? That's your cost. Your benefit is free movement of employees, which means employees have more leverage in a freer market for labor and employers have to run their business well and can't just collect rents on their non-protectable intangibles, like being the only iPhone repair shop in town.

If you had a fair, reasonable standard for non-competes that had statutory limits and were void otherwise and that had to be supported by separate consideration, sort of like how we're trying to do employment arbitrations here, then I might be interested whether this cancels out the BS trade-secret litigation is enough of a benefit to outweigh the cost.

Of course, I doubt it. I've been involved with this stuff for decades and it's never perfect, and I understand that other states might want to be careful about adopting California stuff, but this statute is so old that it's from when Earl Warren was governor.

No one will miss these much. But I think the next question is how to tone down these BS trade secret cases too.

Employers do have legitimate concerns in their IP, but those are protected other ways. Maybe they don't believe that can be done easily. Or maybe it's in your brain and you can't unforget. Well, then the solution is in the IP universe, not in keeping competition out.

tl;dr best argument is that it's the only practical way to protect IP, but this can be addressed other ways both legal (contracts, lawsuits) and nonlegal (cybersecurity), which is exactly what people in CA have done sometimes too much.