> I still, after all these years, hold the belief that facebook failed to innovate because the engineering interview is based on memorization. Having worked with those types of engineers, they can absolutely build exactly what is needed.

I think the fact that so much engineering innovation has come out of Facebook absolutely disproves your thesis. Also, while I've interviewed for Amazon (but not FB), I don't think Amazon's technical interview questions were really any different from any other big tech companies I've interviewed at. They certainly didn't seem to optimize for any sort of "innovation" in their tech questions (to be clear, I'm not sure how you'd do that).