What you said is accurate... but it's like a self-fulfilling prophecy.
"It's not popular because ammo is expensive and they don't make enough different choices in guns."
"Ammo is expensive because it's not popular so the ammo doesn't sell like 9x19."
"Manufacturers don't want to make different guns for it because the round isn't that popular and they fear folks wouldn't buy it."
It's pretty much a circle. NONE of the problems appear to be inherent in the design or execution of the caliber itself. It does precisely what it's designed to do, and quite well.
Attention Brass rats and other reloaders: I really need .327 Federal Magnum brass, no lot size too small. Tell me what caliber you need and I'll see what I have to swap. PM me and we'll discuss.