It's in California, so non-competes were probably not the issue.

A "non-compete" in California is very enforceable. Though not in the way that most people think of non-competes. "I will pay you $X, at $Y per month to not do that thing for the next $Z months. If you decide to do that thing before $Z months have elapsed, the money dries up. Also, the amount of money you receive each month increases with each passing month."

I did a deal with my small company in 2008 where I sold IP. I personally agreed not to go and recreate that IP for at least 5 years, and for that, I would receive revenue share from the current IP.

I also did a deal with a different small company I created at the tail end of 2016 whereby I received a cash payout with an attached clause of being sued into oblivion should I a) attempt to work with the client in some capacity for a period of time or b) talk about client so as not to jeopardise the in-place contracts. The company that acquired my company was interested in the contracts that my company had with a client, not the IP so much.

Non-competes in California are very enforceable, but they usually come with money attached and are not used to bludgeon a Sandwich Artist from earning a living at the deli across the road.

In CA, non-competes are still valid against executives, founders, and any employee with a material share of the ownership of the company (for a multi-billion dollar publicly traded company, a material share can be a fraction of a % of the total value of the company).