World of Warcraft is notorious for this. Making items “no longer available” in the game.
Why should an item become “no longer available”?
The item must be kept in the client forever. Yes FOREVER, since some players will have the items and they must be displayed or otherwise operate correctly when they are used.
If an item is truly “removed” from the game, it must be replaced by something of equal value and there must be an overwhelming reason to remove it. I’m having a very hard time thinking of a reason that would call for an item to be permanently removed from the game.
Removing an item is not the same as changing it. If a weapon or armor piece or set is too powerful, or too weak, then one can easily change the stats on it to make it more in line with the play styles of the game. This is done all the time.
Here are some of the Excuses that game designers have used to remove items from the game, and the reasons that none of them hold up.