"Should" is doing a lot of heavy lifting there. Most shops are a long way off from secure coding, and from my experience in the last 10 years most devs lack basic awareness of security. I still see people being surprised by OWASP Top 10 or simple things like trust boundaries.

There's no guarantee AI will find existing vulnerabilities proactively during coding, or that it won't introduce new vulnerabilities in the process of shipping features. You're right that shops _should_ be critical and test code, but I think due to the lack of awareness people will end up implicitly trusting any first pass written by AI and not bother to double check it.