Or we could give people the choice to either grind for something or buy it. Just because a game has trading doesn't mean people have to use it. There has to be someone willing to sell an item and someone willing to buy it.
(edit as follows): On the note of RNG; I played Destiny 1 for two and a half years. Destiny is an RNG based looting game. I did not get over half the high-end weapons and armor because I had really bad RNG. That's ultimately why I quit, I was tired of doing the top-tier end-game content every week on two characters (you're limited, or at least were, to one raid a week per character) and not being rewarded for it because of my bad RNG luck. Had there been trading in that game I would have played it more and enjoyed it more. Are you saying that because I was unlucky on some RNG system that I didn't deserve to get those items, not being able to progress, and to not enjoy the game because of that?
What it honestly sounds like is that you and the people you have talked to have some very rare items, and don't want other people to have the option to buy them, because you think that would make them less rare, and not as cool to say "I have X item". I hope that isn't the case, but it usually is games like this when the option for trading is ever talked about.
Like I said, just because trading is in a game, does not mean you *HAVE* to use it. It's not like in RuneScape where all you have to do is buy X amount of an item off of the Grand Exchange, which has a infinite number of every purchasable item so it just spawns in a new instance of the item. In this, and a lot of other games, the seller would have to have the item in their inventory and the buyer would have to have the asking price/item of the seller. It wouldn't change the rarity of the item because the seller would already have the item, they are just selling it, so the item is trading hands, not duplicating the item.
(I wish I put this much effort into my essays as I did into this
.)