I think part of that is the iPad mini is much more of a niche device than the other iPads. It has no ambitions to be your next computer so it really doesn’t fit all that well with Apple’s current iPad marketing.
Of course that’s why I started using one instead of my iPad Pro. I got fed up with the ridiculous limitations of iPadOS and decided to put my computer needs back on the Mac. The features that the iPad mini excels at are a good replacement for the few things that the Mac is missing. Pencil, extreme portability, cellular connection, and nearly instant access.