We had the reason right in front of our eyes, just not in this forum, but in the other one.

Straight from the FAQ, from the same people who told that they don't like P2W games and then they made a P2W game: "There's no chance for sharing the drop rates. It won't have a positive impact, it will confuse players. Please, understand that and stop insisting on it. Thank you."

Meaning: "If we share the drop rate, the player will understand how bad they are and how we always screwed them; so they will stop playing the game and give us money".