They realized that as they had structured it, there was really no point in anyone who wasn't a whale paying any money at all. So they changed it so that, for someone who wasn't a whale but was willing to pay a more modest amount of money, the rewards for a one-time payment of $20 are considerable. Unless they change it in a future patch, which they might when you consider today's patch.

The screw-up was in how they tried to monetize the game initially, as they gave away too much for free. At that point, there wasn't a good fix for it.