Well, I think not the inventory-systems alone are the problem, but the way how games seem to be designed around it.
I would really love realistic inventory systems and gameplay that is designed around this concept. You can break down most big RPGs to the following simple gameplay-loop.
Open map, set marker for quest, dialog, open map, set next marker, gameplay-section: kill everything, loot everthing, manage inventory, rinse and repeat.
Let's go through a thought process in FO4 that maybe most of you can relate to:.
[5 Raider corpses on the floor] Will I only pick up the ammo and bottlecaps? Fuck it!
I can still sell those 100 Raider armors, or turn them into crafting material or give them to my settlers or store them in one of my crafted boxes. This is what I call inflation of loot. There is so many stuff to be found that it becomes pointless. Zelda games work differently and to some degree better if you ask me: you have a sword and later you get the uber-power-sword and not 30 iterations of better swords. So you will apreciate the stuff you find more.
The second biggest problem is the fear of leaving something behind that you think might become useful later in the game - Witcher 3 was extremely guilty of this. My inventory was stacked and I never used some of the materials in the end game.
A realistic approach to roleplaying games would look something like this: Picking up heavy armor will slow you down, deplete your stamina faster and making stealth impossible, whilst giving you better protection. When you see a new sword it should be obvious if it is/STAYS better than the one you are carrying. Some may love the idea of 'yeah, but later on that weaker sword may become stronger than this one through upgrades and crafting' but this is a part of the problem imo. It becomes nearly impossible to determine the value of items you find for later in the game. Kudos to the Souls series for at least trying something new.
I have to admit though , that the inventory-management-mini-game in FO4 is still a guilty pleasure for me, but on the other hand this execution of 'roleplaying' is getting kind of dated all across the board. I remember playing my first RPG on Amiga 'Eye of the Beholder' - In my memory this game was like a dangerous journey into the unknown, because it didn't feature most of todays gameplay standards - it was brutal as hell: permadeth, no fast travel no saves and so on. (pls, correct me if I'm wrong - I was young and the discs came without a manual for obvious reasons

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Why do we need 1000 Quests and 1000 different samey items with different stats?
I don't even know how I feel about this: on the one hand I appreciate that I can get 100hours out of the game on the other hand this leaves a bitter taste because most of the stuff I'm doing is redudant and pointless.
Roleplaying games should be about the journey and not goalposts and checklists.
The resources should be directed towards new concepts of progression systems. For example: In a game with 100 Quests, I simply don't have the time, will and incentive to travel everywhere on foot - no, I will make use of the systems in the game that make my time-management more efficient. If the same game is designed aound a different objective all those systems are not needed - think of a RPG with the set-up of a game like Last of us. Your main objective is to reach a certain point - the journey in the Last of us was one big corridor- why not try to do something simple like this with a much more widened game world where sidepaths become organic side-objectives?