The TC is pretty detailed to me, actually. More detailed than the Kryptonite rock that comes with the EX Supes, that I hear was at one time (not sure if it still is) fetching around $70 on eBay.
It is never the value of the accessory itself; it's valued at how much people are willing to pay for it. When demand for the figure at a certain time is high, I presume demand for their accessories, especially EX ones, are going to be high as well.
I hear you. This figure is beefy as is. I merely want to add to one section that's uneven with the other side, a very easy fix considering the zipper is there. Either a little cotton or foam would work fine.