Pov Natasha's:
Just as I thought they came, Greed has always been a predictable bastard in certain aspects, he, like Zenos, likes to plan and prepare before making any kind of move, the only difference between them is that Zenos does it out of fear, his bad luck and the life he conquered with effort always came with its difficulties, but Greed has always been a bastard who thinks he's smarter than everyone.
That's why I knew he wouldn't show up, deep down he's always been a coward who avoids any type of possible risk to himself, especially after being so injured after the Fight against the Saint of Life.
I don't know when he started planning or the types of preparations he made, but I know his behavior, he won't show up until it's explicitly necessary and he'll prefer to run away abandoning his entire plan if necessary if he thinks he might lose this fight.