That's probably an accurate assessment, the question is mainly if the reasoning can be improved to a notable extent and how much on the current architecture.

I myself assumed that we're pretty close to the end of the S curve when first using 3.5-turbo and figured that hallucinations will be pretty hard to overcome, but with GPT 4 being such a massive improvement on all metrics I'm no longer as sure. GPT 5 will probably be more definitive on what's possible, based on where it starts having diminishing returns.