Yes, they're certainly squeezing 500 lines of functionality into 250,000 lines of code. Agents are great at this.
Could be argued they were going downhill before but it's a much faster decline since 2023-ish
Luajit is under 80,000 lines of code.
If I was to employ them to review the code without giving each the same baseline multi-page prompt, they go into endless loop of "improvement" with no end goal in sight.
More and more frequently, I instruct frontier models to stop and go back to the task at hand.