It's just really good weights - significantly better weights than anyone else has.
why has nobody else been able to catchup/come close?
Really good weights that you don't have to run yourself
good weights are the key, but it has python interpreter and bing search. and likely more in development.
Probably a lot that we don't know about, because ChatGPT has better reasoning skills than most other systems out there, and we know reasoning is not really about the weights.
Chatgpt can't reason about anything.
it can pretend, which often looks indistinguishable. so that you can't say if it's real or not.