Why should it be "running back and forth ?
Meaning, they would pick up all they could carry, go back to town and sell it, run back to the dungeon and repeat.
It's again all about choices/balance.You have to adapt your strategy to your choices.
Yes, and I like that. But in the case of arrows, I'm not so sure it would feel that way. For example, consider the special arrows in DOS2, or even the scrolls and potions for that matter. Because there is a limited supply of them, I can be hesitant to use them because of the possibility of a future scenario where I really might need them (unless I remember to shake myself out of it and just say "fuck it"). I generally end up hoarding them. I wouldn't want to have to consider if an opponent was "arrow worthy" (Seinfeld .. sponge worthy ... anyone?) for each and every attack. I could see the end result being a melee character that occasionally shoots, and never the true archer that exists in these fantasy settings.