Aside from TheGilgamesh's solution of making items useless, I find the easiest way around this is simply to tell players to treat the game as though it's a standard pen and paper game. If players are actually roleplaying properly, they SHOULDN'T be picking up literally every item in sight (unless being a klepto is part of their personality, and even then- you just have to make sure there are in-world consequences for their stealing). You just need to get your players into the mindset that they are playing a D&D-like, NOT a standard video game.
