I do not understand how hard it is it for them to make it 100% drop.
They don't even realize how much evolve stones you need from start to finish.
PLUS there are literally hundreds and hundreds of people playing this game. Putting in 100% drop rate on evolved stones wont even put that much of a dent in the economy cuz EVERYONE needs them. And these same people have ALTS that may want to upgrade their soul on their alts so of course, you'll even need more evolved stones. Don't understand why they don't just put evolved stone bundle for Mushin floors 16-20, making floor 2