You're right, it is about protection. A nondisclosure only goes so far. You have to prove in court that the nondisclosure was violated. Because how do you prove that a prior employee gave that knowledge as opposed to Pepsi just reverse engineering it?[1] A noncompete is an extra layer of protection because the barrier for proof is lower. You don't have to prove they violated the NDA, you just have to prove they work for the competition.

You recognize that these are different things, right? I stressed that it can be subtle, but if you're having a hard time recognizing they are different then please give it a little more thought.

A noncompete *also* means your previous employee isn't taking institutional knowledge and training with them. These won't be covered by a NDA! As an employer you invested in an employee by training them, right?[2] So you lose that investment?

The reason I put so much stress on this second part is because it is exactly what the above conversation has been about. The employer is thinking in the instant and narrowly, not more broadly. Yes, you lose employees you invested in, but you can also get employees you didn't invest in. That's the bigger picture. Plus, you can... you know... pay your existing employees more than you pay new employees with similar skills. Instead of threatening them against leaving incentivize them to stay. You get a bigger return on your investment anyways

[0] personally, I don't think it justifies having them but we can still understand the reasoning, right?

[1] this is something most people with an undergraduate education in chemistry could probably do. So good luck

[2] I stressed this above