Developers greed reflected by Economy Changes brought this game to a state where after investing considerable amount of time (a.k.a. reaching top tier) it becomes pay to play.
It's basically a psychological trap - the time invested into the game pressures you into spending real money.

Developers greed reflected by Economy Changes brought this game to a state where after investing considerable amount of time (a.k.a. reaching top tier) it becomes pay to play. It's basically a psychological trap - the time invested into the game pressures you into spending real money.