Not because you make money from selling any Runs, it's because you have to go with at least 1 friend (or you play Summoner *cough cough*). There aren't any Things in this game now which you HAVE to do with more people besides F7. Good for Soloplayers, of course, but i loved to do a few Elga runs with friends if they had to for their Rare Parts.
un-restricting elga ingredients does NOT restrict you from having fun farming with friends, it's either you choose 2 options : 1 go farm with ur friends have fun, 2 go buy ingredients and help your friends. Want both? then go farm gold with ur friends have fun yay doing same thing over and over like in elga, and buy ingredients to help your friend.
Please think about other people who does not have any friends and cannot afford elga runs , solo or with friends =D *tag oniichan have no friends in DS :3 *