From a political theory perspective, by the Allagan Empire's fall a flag no longer served a purpose, really. Flags are used to represent an identity and identity is a relative thing. That Canadians exist gives meaning to being Italian. But by the end of their era, Allagan was the state of being for everyone that wasn't Meracydian.
Flags also are used to boost morale, but by the fall of Allag there were almost no organic soldiers and few organic laborers. These classes that often rally around the morale boost of their trials being for the good of all just didn't exist anymore.
I would say that Meracydia might've had a flag, because they needed symbols of an identity distinct from Allag, but Allag had no need to differentiate itself from anything. People were Allagan. Allagans were people. Things outside this weren't really worth considering.
In this way, Allag isn't comparable to an ancient power, but a future one. Allag was very nearly a Type One Civilization, which has never existed in our world so is mostly speculative. We just have political philosophy and theory to project what one might be like and, in this case, why it might not bother with flags.
Flags also are used to boost morale, but by the fall of Allag there were almost no organic soldiers and few organic laborers. These classes that often rally around the morale boost of their trials being for the good of all just didn't exist anymore.
I would say that Meracydia might've had a flag, because they needed symbols of an identity distinct from Allag, but Allag had no need to differentiate itself from anything. People were Allagan. Allagans were people. Things outside this weren't really worth considering.
In this way, Allag isn't comparable to an ancient power, but a future one. Allag was very nearly a Type One Civilization, which has never existed in our world so is mostly speculative. We just have political philosophy and theory to project what one might be like and, in this case, why it might not bother with flags.