For recent model and higher end games, the saturation is real and it will hurt new game sales.
One of the most crazy things about this hobby is that these things have held almost all of their value when we go to sell them. I don’t know of many luxury items that hold value like that. Supply is catching up with demand. This is changing somewhat and will cause many to think twice before a new in box purchase.
Wait until Deeproot actually releases something. It will accelerate. The addressable market for NIB buyers simply isn’t that huge.
But for older / more affordable (call it less than $3000) model games, they are NOT going down in value in my experience. I have sold over 30 games since being in this hobby and most of them are in this category.