That's an interesting claim, but I don't see it in my own work. They have got better but it's very hard to quantify. I just find myself editing their work much less these days (currently using GPT 5.4).
In particular GPT 5.4 is much better at not duplicating code unnecessarily. It'll take the time to refactor, to search for pre-existing utility functions, etc.
You kind of have to go on "feels" for a lot of this.
Most of us have been coding for ages. I actually find it really odd people keep trying to disprove things that are relatively obvious with LLMs