What GPT-3 lacks that seems to be crucial, is a consistent view of the world.
For example, if you ask me "what is the capital of France?" I will answer "Paris" with 100% probability. No matter how you phrase the question, there is simply no other answer that can be given, if I understand what you are asking.
It turns out that humans, despite their reputation, are actually very good at avoiding cognitive dissonance.
Whereas language models are very bad at it. We don't even think of GPT-3 as having cognitive dissonance because there is not a gram of consonance in there.