You get why? If, after the looms were introduced, we remove the upkeep we won't need a gold income anymore as gold would only be used to buy looms then. But if you want to buy looms you should have retired yourself before.
Remove upkeep -> remove gold income -> make items in shop purchasable for 0 gold -> looms on the market are only traded 1:1 for other looms -> no gold included any more -> people dont need to use peasant gear once in a while till they can use certain more expensive items again -> everyone happy?
Imo gold income was always meant to a) either buy gear you don't have from the shop and/or b) cover your upkeep. Not to buy looms, you get looms by retirering after all.