The comparisons with models like GPT-5.6 or Opus are pointless because they vary substantially. They are often nerfed shortly after release and then performance is not consistent. One day model will be doing relatively fine, another it will be dumb as markov generator. In that regard self hosted models are better, because you know what is running your requests.
I mean the efforts you linked are showing there aren't actual nerfs happening, making the alternative explanation of people just 'growing into' the capabilities of models more likely to me
