Possible solutions: Create a new form of millionaire (to modify the one that this one) that must leave within the game that million and that allows them to continue doing the millionaire with low requirements as until now.
2: A waiting time to withdraw the million from the game (in case you only implement this) 2 days, 5 days, 10 days or whatever suits the economy of the game.
Create an island that costs 1 or 2 million Starbits and you can do a mission, bone as a pool that the player have the island receives 10 thousand Starbits or 20 thousand if you buy the island that costs 2 million (do it as simple as possible to not have to do so much coding)Create more special edition cards (people from the community who are fans of Rising) so it is not necessary to be an artist and you can recognize players who are not musicians, the same provide a number of fans depending on the fans that owns in the game, they sell themselves at Starbits and burn more and more.
Do more things that require Starpro as you have been doing.
So I could continue writing many ideas that could be taken into account to polish and see which ones are feasible to implement and that do not require coding that can damage the engine of the game, I know that we will have game for a while because you have proven to be a responsible person who stands up for this game, I always think