I don't think that's exactly it. OSS only needs someone to have a strong LLM to check for bugs. If your software is proprietary, it's a competition between just you and whatever model you have vs any attacker and whatever model they can lay hand to.
> OSS only needs someone to have a strong LLM to check for bugs.
The same applies to propietary, closed-source code. It being closed-source means that the source isn't generally available, but the executable is. Hence, someone with a strong model can still reverse it and find vulns.