I don't see why game designers should try to mechanically resolve what is pretty much a player's problem.
If a Paladin is blowing huge chunk of gold on armor without leaving anything for other characters, chances are he'll also act carelessly and unilateraly during fights. And it may end with Wizard not having had the chance to learn a spell that would have proved lifesaver at some point, or a ranged Fighter/Rogue/Ranger getting an indispensable magic ranged weapon and ending up being half-efficient when it counts the most, etc...
If a Wizard scribes down every scroll he finds without first wondering if X or Y spell would really be useful to party, he's also probably using whatever spell he likes without considering how well it synergizes with party and preventing possibly the martial friend that has been tanking for him to get a better armor, ending up being struck down regularly at some point, and then Wizard will get it too.
Making gold "individual" would simply move the problem instead of lifting it: you'd now have individualistic players rushing to loot whatever they can exactly like the worst players in the worst hack&slash games. And it wouldn't at all resolve the "how to efficiently share and use the loot and wealth" and player discussions on whether to priorize ingredients, weapons or scrolls, just amplify it because of those individualistic / egoistical behaviours being pretty much obvious every step of the way instead of being restricted to the short moments where players interact wiht merchants.
If a person is not able to put emphasis on teamwork, then (s)he should probably avoid playing multiplayer in the first place, it would just end frustrating for everyone, self included... xd