Gary, I am astounded as you are. But the fact is, there is a higher demand for all Ultra Rare Gems as evident by the prices offered on eBay and elsewhere. And just based on the eBay prices, the Sapphire would have been even more of a markup.
I am not sure what the logic was for the person who bid $45 for the Sapphire but it doesn't matter. If it were only worth 400gp then the price would have been $10-$15. The fact that multiple people bid $40+ says that there is a special markup placed on these gems.
Aside from that, the GP to $ ratio is locked based on the tokens that are being sold for $ and their GP values. If this ratio is locked, then the $ values of the URs, by definition must have the stated GP value, ragrdless if anyone can pay it or not.
Look at it this way:
Are you saying that a Sapphire is worth 550gp yet worth $45 on eBay and Gauntlets of Ogre Strength worth 500gp is only worth $15? This doesn't make any sense. Is a Sapphire for the Gauntlets and even trade or no? According to your GP values, almost. According to your dollar values, not even close.
"I do not feel obliged to believe that the same God who has endowed us with sense, reason, and intellect has intended us to forgo their use." - Galileo Galilei