Even if was noticeably better, Scam Altman hyped up GPT-5 endlessly, promising a PhD in your pocket, and an AGI and warning that he was scared of what he created. Progress has kind of plateaued, so it isn't even really noticeably better, it scores a bit higher on some benchmarks, and they've patched some of the more meme'd tests (like counting rs in strawberry... except it still can't count the r's in blueberry, so they've probably patched the more obvious flubs with loads of synthetic training data as opposed to inventing some novel technique that actually improves it all around). The other reason the promptfondlers hate it is because, for the addicts using it as a friend/therapist, it got a much drier more professional tone, and for the people trying to use it in actual serious uses, losing all the old models overnight was really disruptive.

There are a couple of speculations as to why... one is that GPT-5 variants are actually smaller than the previous generation variants and they are really desperate to cut costs so they can start making a profit. Another is that they noticed that there naming scheme was horrible (4o vs o4) and confusing and have overcompensated by trying to cut things down to as few models as possible.

They've tried to simplify things by using a routing model that makes the decision for the user as to what model actually handles each user interaction... except they've screwed that up apparently (Ed Zitron thinks they've screwed it up badly enough that GPT-5 is actually less efficient despite their goal of cost saving). Also, even if this technique worked, it would make ChatGPT even more inconsistent, where some minor word choice could make the difference between getting the thinking model or not and that in turn would drastically change the response.

I've got no rational explanation lol. And now they overcompensated by shoving a bunch of different models under the label GPT-5.