The Amazon recommendation system is still dumb, despite supposely being trained in my tastes for years now. I wish for Lovecraft scholarship therefore I will like… Dennis Wheatley, The Devil Rides Out. Er, no.
I think the general problem arises from lumpen categorisation systems, which are auto-sorted according to publisher supplied metadata and then parsed by artist/writer. It serves publishers well to make their tagging of a product as broad as possible. But a recommendation system needs to be able to make fine distinctions of taste, and do so even within artists. Such as knowing that Ziggy-era Bowie is not the same as Tin Machine-era Bowie. Or that Midge Ure’s Ultravox is mass-market pap compared to John Foxx’s Ultravox.