I'd take that bet if it was measured in "bugs per day" instead of "bugs per LOC". LLMs generate far fewer bugs in absolute terms, but they also generate far more code, so it probably balances out if everything is equal. I think LLMs will actually lead to more bugs just because they're usually working with poorly defined requirements (prompts) and they guess to fill in the gaps based on the averages of their training data. A lot of those guesses are wrong.

Where LLMs win though is the severity. An LLM will write buggy code in the sense that it doesn't do what you wanted it, but not so much in the sense of security or data loss bugs. They get that right more than humans because they're trained to care about that stuff. There's far more "how to write good code" content in the training data than "how to not care about security and go fast" content (because writing that would be weird!)