Otherwise, yeah, generally when something is released sub-only, it is because it is too niche to justify a dub.
Here is a question,
Why does Bandai Visual USA sub only dvd's cost so much?
Because they all failed economics.
But, seriously though, looking over their titles, I don't see anything that could possibly cost an arm and leg to license(and justify Japanese pricing for sub-only dvds). Pretty much all of them are niche titles anyway. Super Robot Wars, Haruka, MS Igloo...
I suspect BVUSA reasons that anyone who's actually interested in buying their titles will buy them anyway regardless of the pricing, and probably won't care about a dub anyway...and then they hope the prices will partially offset the low sales.
They can charge a premium if they want to. Whether, it's a particularly good idea is something else.