1) Supply and demand. It's not the same sized market as SBC/BBC/SBF, or even BBF.
2) Size and weight. Our rods are very large and heavy, which requires more metal, and more machining.
If it's any condolence, Cummins and Powerstroke aftermarket rods aren't any cheaper.
Wade Moody is hyping aluminum rods, which can be substantially cheaper. But the jury is still out on how well they work in daily drivers. I would be cautious. The amount of money you save doesn't come close to what a rod failure will cost you.
DuramaxTuner tried to put $1750 rods on the market by cutting corners, but they proved to be no stronger than OEM rods, if that strong.
Even high-$ rods can be risky. Cunningham is selling Dmax rods (not many out there IIRC), but they have collapsed on at least 1 engine that I personally know of.
I've tested both Crower and Carillo rods, by measuring them, then beating the crap out them, and then measuring again. AOK based on my testing.
I haven't tested Howards or RSR/TTS? rods yet, but I haven't heard any complaints.
I'm a rod consumer, not a dealer. For now, any engine I run will have Carillos or Crowers in them, with a nod to the Carillos since the Crowers are .010"-.004" longer than stock, and the small end is not as wide, which puts a higher load on the wrist pin.