In the end, money matters. Similar to any other sports body, FIFA also makes sure that they get the maximum amount of revenues from each edition. But I will not blame them for becoming overly greedy. They have somehow managed to find the optimal balance between profit making and keeping the fans happy. Expansion from 32 participants to 48 was mainly done to give more representation to African and Asian teams and not for money. If they want to make money, then they can easily conduct the world cup every 2 years instead of 4, but they haven't done that.