To each their own, but I wouldn't consider playing D&D for nothing but the loot to be a real investment. The only investment we have been told of is time on this guy's part, and even that is split with whatever he is doing on his phone, so he is not really losing time by playing. All together, based solely on the descriptions given, he shows almost no actual investment UNTIL he felt they had been screwed out of an item.
EDIT: I should add, I don't have any problem with those who play for loot, I am simply saying that D&D gives rich options for character and world development, and that these two take far more investment than simply collecting whatever loot is thrown at you.