While I agree that handcrafting code has never been any kind of guarantee of secure code, I'd argue that it remains a condition: if all you have is a set of specs (or even worse, specs written by AI and not read carefully by anyone) and no mean to ensure that the implementation actually matches the spec, you essentially have no understanding of what the code is doing, which is security suicide.

Of course, AI reviewers and security tools will catch some security errors, but this should come as an addition to a proper security design, not instead of it.