I hope this question can be answered by the dev. team.
Can it clear what we get if we spend X-dollars or share the general earnings the game expects/needs? A pay scheme expectations for the power/competitive folks, for the long time causal loyal players, for free to play players that will shell out on special occasions, or players that will always be free to play. I believe you have customers in each segment and if the right set of expectations are set for each you shall be reward with your goal of increased revenues.
As a Disney game, I find it hard to recommend my kids and younger relatives to play this game and enjoy it.
For example, if you spend around X , then you will likely do well in X events and place in the top.