If your bet is on the former, how does it create an entirely new, irrational thought?
The AI's we are using now are nearly one dimensional when it comes to information. We are pretraining on text, and we're getting "human like" behavior out of them. They have tiny context windows when working on new problems. They have no connection to reality via other sensor information. They have no means of continuous learning. And yet we're already getting rather insane emergent behaviors from them.
What does multi-modal AI that can interact with the world and use that for training look like? What does continuous learning AI look like? What does a digital mind look like that has a context window far larger than the human mind ever could? One that input into a calculator faster than we can realize we've had a thought in the first place? One that's connected to sensory systems that span a globe?
We also have some pharmaceutical tricks to tweak up processing capabilities of the mind, so there's potentially no need to simulate. The capabilities of the big ball of sentient goop have not been plumbed yet.
Now imagine a technology that could obviate the need for sleep or maybe make it useful and productive.
Arguably humans are the same, being the product of genetics, epigenetics, and lived experience.
Current "machine learning"-style AI (even when it uses self-driven iteration, like the game playing systems) is the result of a few ideas across not much more than 100 years, and for the most part is far too heavily influenced by existing human conceptions of what is possible and how to do things.