What's the conversation that you're looking to have here? There are fairly widespread claims that GPT-5 is worse than 4, and that's what the help article you've linked to says. I'm not sure how this furthers dialog about or understanding of LLMs, though, it reads to _me_ like this question just reinforces a notion that lots of people already agree with.

What's your aim here, sgt3v? I'd love to positively contribute, but I don't see how this link gets us anywhere.

Maybe to prompt more anecdotes on how gpt-$ is the money making gpt—where they gut quality and hold prices steady to reduce losses?

I can tell you that the post describes is exactly what I’ve seen also: degraded performance and excruciatingly slow.