I dunno man, if there's a deluge of new AI generated code at all layers of the stack I think there will still be vulnerabilities.
Like if we were willing to stop adding new code and just have a small secure code base, AI could maybe help us find all the vulnerabilities in that code base.
But people have consistently been unwilling to do that. Like if we were willing to stop adding code we could have stopped decades ago and done SQLite level testing everywhere and probably have found almost all the bugs already.