-1 for the inflation idea, it will just hurt the people you implying that you want to help.
The only real way to target the people you mentioned is to introduce a tax system in the game, for example if someone has more than 100m then 1.5 of their income will automatically be deducted every week, if they have more than 500m then 2.5%, if they have 900m+ then 3.5%. Those numbers and time are just examples. But I don't think a tax system will ever be introduced to the game.
And for the argument that they could convert their money to items, the way you can have items is very limited, for example new coin capsules can only come from donations and for rerolls, you need to work for them and so it takes some time to generate new ones in the game too.