Why Do 12" Tonearms Cost So Much More Than 9"?

For example, the Tri-Planar 12" arm is $3600 more than the 9" version.  SME tonearms are similarly priced.  
Is it really that much more costly to develop the longer tonearms?  
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Why do tone arms cost so much in the first place? Because not many are made. A lot of special tooling that is not cheap is amortized over not very many units sold. With 12" its even worse. There really is no advantage worth that kind of money. For the difference in price you can get a much better 9" arm. But just try telling that to anyone who bought into the 12" narrative. They probably have some special alignment jig that cost a small fortune that they swear by as well. And so on it goes. 

Look on the bright side. At least its not bi-amping.
I never realized the 12" version is more expensive dis-proportionally. Miller, you're very correct about bi-amping! Similar to when stereo came out and a husband had to explain to his wife why "they" needed another amplifier and another Hartsfield in the living room!!
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