And the stuff it is good at are not bottlenecks.

Disagree. Code review done right is a virtually impossible bottleneck for most companies to handle, so in the past they didn't do it and we have the shitshow of security and other bugs that we are experiencing today.

If you removed LLMs from the face of the planet today, code quality will not suffer significantly.

But LLMs aren't going anywhere, and they are already being used to find vulnerabilities by hats both white and black. They are also finding functional bugs that affect life safety and financial stability.

Code was fine for four decades

The way that municipal water was fine for centuries before chlorination. Cholera outbreaks were just one of those unavoidable realities, like mass school shooting events in the US.

if a machine learning model was purpose made to do code review, instead of general purpose LLMs doing it, how much better it could be, if we actually leveraged what they’re good at.

From what I have seen over the past year, this type of specialization is happening, and the progress is real and significant.