That's definitely an improvement, but it's just one aspect of cybersecurity. Logical errors allowing people to e.g. log into services and extract data are likely everywhere still.

If we can eliminate entire classes of bugs from being possible. It frees up resources to investigate the ones that are still possible.

I suspect after a few years of LLM assisted bug hunting, everything will have a baseline security that is very good. Much like how stronger viruses simply create stronger immune systems.