i think what nguyenhuukhoinw is asking is why the buildings' architectural style don't change with phase advancement, similar to how they did throughout the AOE series and in some other RTS games. the answer is simple: phase advancement doesn't represent the passage of time like advancing from the Stone Age to the Tool Age in AOE1, it represents the level of sophistication that your faction is going through. iirc, the idea is that you're not playing as a fledgling civilization in an untamed world, you're playing as a colony of that civ far and away from where they're supposed to be (usually)