Since it's relative to scale, they -could- reduce the cost and price and gain of everything to 1/10th of current (riotes drop 3,200 coins instead of 32,000, repairs cost 12,000 instead of 120,000 etc), which would effectively make.. well, what was 21gbs be worth 2.1gbs, meaning you could buy something that WAS worth 210 gbs for 21gbs.
The problem with that is that 95% of KO would be confused as hell for weeks to come, and they'd get six billion CS tickets saying "OMG MY MONEY IS DISAPPEAR HELP PLX".
And tbh, KO's economy would be fairly reasonable/balanced if DUPING was never an issue.
As for 21gb in market stall, it limits you to that ONE item, 'cause if you put two items up for a total of 25gbs and both sell, you lose out on 4gbs. At 10gbs this happens less frequently.