It's a re-welcome for me. :P I see where you're coming from, but this could still just be probability. Say you put all the trophies in a bag, and you put the trophy back after it is picked. (Idr what the number is, so let's go with 610) If you have never pulled out a trophy, you have a 610/610, or 100%, chance of getting a new trophy. If you take out a trophy and replace it, you now have a 609/610 chance of getting a new trophy. The number keeps going down as you get more, so this makes it harder to get new trophies. This isn't so much rarity, as it is simply getting repeat values (trophies in this case). Once you get about 550 trophies, the ratio of getting a new trophy is only 60/610, or about 9%. It's not to say that all trophies have the same rarity, but they definitely have pre-defined chances, and they most likely do not change.