> I've read a lot of the scientific literature on human creativity (there isn't much) and it is quite clear that we don't understand it at all.

I don't agree that this is true in any way that precludes the creation of "true, autonomous AI". We may not understand the specific mechanisms of how our brains give rise to creativity and the resulting "implementation artifacts", but the fundamental part of creativity (and I'd argue, the part that's relevant to AI) is the ability to efficiently search huge but structured hypothesis spaces and inductively learn new structure (very likely with some stochastic element involved).

That is something that we not only have an understanding of, but have implemented, more than once. By way of examples:

http://www.popsci.com/scitech/article/2006-04/john-koza-has-... http://aliciapatterson.org/stories/eurisko-computer-mind-its... https://psmag.com/triumph-of-the-cyborg-composer-620e5aead47...