I don't understand the point of your question. The "problem" of an ex-employee consciously or subconsciously bringing his learned experiences at your company to a competitor is literally the reason why non-competes exist. In fact, this topic is quite old.
It is also illegal in CA.
My real point is this: if you're not allowed to bring your experiences with you, then the company exists to extract your creative thinking and skills. You can argue that's a fair trade for money. I don't necessarily disagree. But I think most of us find joy in learning, in building our own skills, in being able to reapply them elsewhere. And before LLMs and agents, I couldn't lose those skills and experiences no matter where I worked. As we progress, though, we've hit a point where we have to ask ourselves: at what price are we willing to trade complete ownership of our thinking and experiences for money?