I don't like having to invest time preparing a meal, baked goods, etc. -- only to be *disappointed* in the outcome. E.g., 12 hours to make 16qts of "spaghetti sauce" would have me grumbling each time I consumed any of that batch if the "tomatoes were lousy"! (and the idea of DISCARDING all that sauce is anathema to me!)
Driving 20 minutes to the nearest "oriental grocer" that *might* carry the items we seek (and, more often than not, *won't* have stock on hand) means its more effective to drive *45* minutes to the grocer that *will* have stock! Having invested that much time, you don't want to buy "QTY 1" and make the trip again next week! (so, we buy "case lots" just to avoid wasting all that travel time)