OpenAI themselves discourages using GPT-4 outside of legacy applications, in favor of GPT-4o instead (they are shutting down the large output gpt-4-32k variants in a few months). GPT-4 is also an order of magnitude more expensive/slower.
I think both of these points are what sow doubt in some people in the first place because both could be true if GPT-4 was just less profitable to run, not if it was worse in quality. Of course it is actually worse in quality than 4o by any reasonable metric... but I guess not everyone sees it that way.
ofc 4.5 is best, but its slow and I am afraid I'm going to hit limits.