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

the real deal

https://www.artisanfidelity.com/tonearms/ikeda-it-407

Thank you Mijo again.

The CB also looks very interesting especially in the CB-L version.
I also see there is a collaboration between Frank and Peter at Soundsmith to produce an arm called the Alto at $6k although information seems to be a little sketchy on that?

In my opinion, having heard a few of them, the Schroeder tonearms are indeed very good and very competitive at their price points, but not necessarily better than all of the competitors at those price points.  The LT is desirable for someone like me just because of the clever design and brilliant execution, although I cannot imagine that moving the whole pivot as the cartridge traverses the LP is done without adding friction that must be overcome.  On the other hand, I am a cheapskate so won't be buying one.

. On the other hand, I am a cheapskate so won't be buying one.

Thanks Lewm!
Gave me a good chuckle there👍😂

Lewm, The brilliance of the LT is that it is using the energy from groove friction to drive the arm! Friction pulls the horizontal bearing platform forward and a magnet underneath makes sure it maintains the right position. 
Uberwaltz, I am not entirely sure but I think the alto is a version of the CB.
The CB is as good as a pivotal arm can get for several important reasons. 1st is the vertical bearing is at the level of the record which limits warp wow. 2nd is it is a neutral balance arm. You can draw a line from the center of the counterbalance through the vertical bearing right through the center of the cartridge. Most other arms are static balance arms which always try to fine one level whereas a neutral balance arm will stay where you put it and won't start bouncing. 3rd. It has a brilliant magnetic anti skating device. No friction. 4th it is not a unipivot and has excellent bearings. Need I say more?