Hoi Pine,
The ontology of Wikidata has nothing to do with English Wikipedia. The notion that English Wikipedia is the only endless resource of free labour is pathetic. Its dismissive attitude prevents functional contributions that will benefit the users of Wikimedia projects.
For authors of "scholarly articles" we have an increasing amount of information that is impossible for Wikipedia to include. It does not take much to have a template that show them (standard collapsed) and links to "Scholia" information for the paper.
For authors of books we could have a similar template. They could link to *your local library* where you can check if it is available for reading. Alternatively we could link to the "Open Library".
What it would do is provide a SERVICE to our readers that is easy enough to provide, that leverages the data in Wikidata and is of a high quality. The issue about the ontology has everything to do with the discovery of images in Commons. It cannot get worse as it is, it is disfunctional. It only works for English and I understand that is something you do not really notice.
Yes, I do recognise Wikidata is a wiki. It is a work in progress and as such the quality and quantity steadily improves.. Just like English Wikipedia.
Thanks,
Gerard