I would say we generally expect it as part of our groups' social contracts. Loot is divided up by giving it to the character that can best use it, and secondarily by who is the most behind on loot if the loot is usable by multiple characters. If a character needs to pursue a certain plot hook, we do some mummery of pissing and moaning about it but we always pursue that hook.That's how I've usually seen it. As you say, it would be nice to always be thinking of others, but I don't think it's necessary or should be insisted upon by or of the players in your group
Basically, we have a strong social expectation that the players be chill. Loot is no big deal, progression is no big deal, and if something happens to your character, you laugh it off and start a new one. We all work together so everyone is having a good time. Roleplayers don't complain about combat, and combat lovers engage in the roleplay.