Why does AI-generated code get worse over time?
Because each change reads the previous output as if it were deliberate. An accidental pattern introduced early becomes the observed convention, and later changes reproduce it. The model is not degrading. It is faithfully copying something that was never a decision.
From Why AI-generated apps fall apart in week three, published 9 August 2026. That article is where the reasoning behind this answer is set out, including what it does not cover.