If it can be farmed, it means that it can be also farmed in large quantities. Our playerbase has proven to be able to concentrate on the most boresome tasks to gain profit.
Alright then there's another issue. If for example BoS wanted something, it has to mean that they lose something if they don't get it. But if they do get what they want they should also gain something. What I'm talking about here is causality. If you donate ammo to BoS it should naturally mean that they become stronger. If nobody donates, they won't get any stronger and would eventually even lose their strength. If nothing happens there's no point in the whole quest. Why there's no point? Because if there is no causality, there is no multiplayer activity because everyone can simply get that 5mm ammo alone.
We already got some quests with absolutely no point except to give some newbies starting cash. Good example is cargo hauling or spear-selling, completely pointless and all the same whether someone does it or not.
Removing npc traders isn't needed. I just pointed out that there are games without any npc merchants and have working economy.