I mean, you don't need to run it all the time, right? You do it once over your entire existing codebase to start and then once over the diff in your CI/CD pipeline when you make a new change. I'm sure it's not literally that simple but I doubt these need to churn 24/7/365 either.
You are supposed to run it on full codebase before any single PR gets merge.
Companies don't make production pushes yearly. For many, it's two week sprints..and that's one project.
This doesn't make any sense cost-wise. It would be cheaper to just hire a security engineer.
In the Mythos blogpost they revealed to run the model like a 1000 times on the same code-base maybe with slightly different prompt or temperature. That suggests it will just be pay to win. If the 'attacker' spends more money/tokens than the 'defender' you will eventually be outclassed.