The VSCP would be shared across all vendors and all players. Think of it as the “total amount of gold out there”.
For round #s sake, let’s say there are 10 players, 5 vendors, and the pool seed is 10K per account. Then each vendor would (at the start) have a split of the total 100k pool (20K ea. for this example), and subsequently get a disbursement every time a new account is added.
Then, as you play / loot items, they are sold to vendors for $, and you subsequently spend that $ on other vendor gear, skill upgrades & respecs, gambling, and eventually crafting mats & Bazaar Fees, etc, wherein each expenditure returns the gold to the respective vendor (the pool).
Yes, the return methods need to be conducive to the gameplay, but it is easier to manage deteriorating gold availability than trying to deal with constantly attempting to account for an ever-increasing supply of currency, generated just by playing the game.
Also, if you are using a closed system like SGS, there is no way that someone can ‘farm gold’ directly. At a minimum, it would be very convoluted and require multiple points of transaction in order to accomplish. (Farming items, selling items to vendors to get the gold, then somehow using the bazaar to overpay for items posted by the person you are selling the gold to.) All of which can have stop-gaps put in place to prevent.
Assuming botting and RMT of in game items and currency stays against TOS/EULA and will remain a focus of EHGs, culprits of these types of actions would be easily flagged and actionable through server-side transaction metrics and heuristics.
As for exploits and dupes, that’s just coding issues that can happen in any game, and hopefully they are taken care of quickly.
The other nice part about SGS, is the total gold in the system can be monitored and devs can quickly ascertain if something is awry just by doing a simple calculation server side.
Not to mention, gold no longer needs to becomes an object (in order to drop on the ground from a mob). Gaining and spending currency is basically just a journal entry akin to cryptocurrency.