I don't think this is exactly true; adding holes only happens when adding features, and while LLMs can add features fast, deciding what features are actually wanted and needed is still a human factor.

So the amount of new code added is limited by processes and product management. Add to that that newly added code can get a lot more checks on it now, and new code will be more secure too.

I also don't think your main premise (adding holes faster than we can find them) holds up, but that's another matter. TL;DR I think we're in a high intensity period right now, but this time next year it'll be quiet in comparison - possibly quieter than before AI code scanners were a thing.