I'm not sure. I don't know about deep expertise and mastery, but I can attest that my fluency skyrocketed as the result of AI in several languages, simply because the friction involved in writing them went own by orders of magnitude. So I am writing way more code now in domains that I previously avoided, and I noticed that I am now much more capable there even without the AI.

What I don't know is what state I'd be in right now, if I'd had AI from the start. There are definitely a ton of brain circuits I wouldn't have right now.

Counterpoint: I've actually noticed them holding me back. I have 20 years of intuition built up now for what is hard and what is easy, and most of it became wrong overnight, and is now limiting me for no real reason.

The hardest part to staying current isn't learning, but unlearning. You must first empty your cup, and all that.