Most people have < 10k gold. This was actually recently discussed in a blue post made on a thread about raising the maximum gold transfer cap between servers.
I see the seller doing something slightly different, here's why: The BoE gear is quickly dropping in price on most servers. On Drenden-A, if you're LUCKY, you can find a buyer who is foolish enough to pay up to 12k for both pieces. Last night I saw a player offering to craft either piece, 3k for the gloves, 6k for the chest. Spellthreads are below 1k each. So no matter how you swing it, those Imperial Silks aren't even worth 1k each, except....
The bag. For my server, the bag sells for about 20k most of the time. Almost always in trade, very rarely have I seen one in the AH (there was one up this morning for 24k). This probably means the crafter hasn't actually made the bag yet, they are wiating to find a buyer, so they even have some flexibility.
Since the crafter can only make one silk per day unless they are farming SoH like crazy, and the price of the BoE gear is steadily dropping, that means that the approximated value of the silk will fall with the value of the crafted items. BUT, there is an item that no one is currently making, which would take some time to make, that will sell for 20k in about a week. Seems to me like the value of waiting a week to sell the satchel doubles the value of the silk, all without hurting your ability to use the silk for robes, gloves, or spellthreads.
And during that week it takes you to sell the bag, you can have one or tow more ready to sell the next week...