Gold Sinks seem to be designed in absolute amounts of currency, but the economy is in relative currency. A vendor purchase/sale or a crafting expense is asserted to be x amount of gold. But the market does not value x amount of gold at any particular rate, and it changes irregularly and often.
What can be bought with 1 million gold today might require 2 million gold tomorrow, but the vendor prices and crafting expenses don't automatically respond to that. I'm guessing that the gold sink prices will receive manual updates with a series of patches.
This first leads me to an interesting idea(maybe the reason behind your post, implicit or explicit). What if those gold sinks were some % of the total gold in circulation. Seems it would be an auto-correcting set of gold sinks.
The second thought is one gold sink, crafting, makes items which already scale with inflation. I'm sure this was by design. It's currently not scaled correctly, let's see how that plays out. This could be a reasonable if blunt instrument they can use to address on a patch timeline(i.e. slowly given market volatility) to adjust the currency market.
My third thought is what are the implications of a)absolute value gold sinks quickly outpaced and relatively slow responses in patches and b)the more reactive, but possible overly heavy-handed changes in crafting prices.
One very important sidenote, the changes in crafting prices reflect a balance in the power of playing the game as a game versus playing the crafting subgame, so if crafting becomes dominant, it could ruin gameplay for anyone interested in generating wealth.