Well, then they don’t have to and they can roll for it. Unless they want to hand it over, even under the misguided hope that others will do the same. Do you at least agree this helps for less rare things, like 2-10% drops?
If it’s easy to farm yourself, why aren’t you hunting it on your equally as important alt? Farm it on the character who needs it in your own time, then. Why should somebody who isn’t playing get a free item?
It still helps you anyway, no matter your stance on the issue, because as it stands now one person can get every single important drop since every item is treated equally. The ultra rare super weapon / recipe / accessory or whatever that just dropped is randomly distributed alongside the guaranteed trash material.
You’ve got 4 characters to gear up, and need a ton of silver for various things. I understand that, I really do. But right now you could farm items all day and not have anything to show for it because the guy next to you just happened to get it all. He’s rich and his 4 characters now have good gear, and he needed you to kill the mobs that dropped them in the first place! Thanks, guy!
With a simple rarity/star rating tiered loot system, everyone currently playing will have something to show for their time invested. As you said, any item can be useful to everyone, even if it’s simply to sell, and a NBG system helps ensure that nobody gets screwed because they dared to party up for group content.