Why Warhammer and Star Trek novels receive less attention here

Have you read any Warhammer 30K or 40K books?

Yes, along with some Star Trek and Star Wars novels. Dedicated channels already cover those franchises, so the selections here give more attention to other series.

Warhammer, Star Trek, and Star Wars include books worth reading. Their dedicated channels already provide extensive coverage, which leaves less reason to repeat that work here. A search for Raven's Course and Peacekeepers of Sol found much less material. That was a limited search through the first few results pages, with the additional caveat that YouTube personalizes its results. The choice reflects an interest in less widely discussed books.