> My new suspicion is now that they didn’t got drastically smarter, but they got trained on the user input on the previous generations

I think this happened around Opus 4.5 or 4.5 and the same for GPT 5.4.

The more I use those models, harnesses, techniques for guidance etc etc. The more I land in going back to writing software by hand again. Maybe not all of it, but at least the crucial parts + foundations.