A funny quip to be sure. But one could be counter-pedantic and say the title never promises empires. It promises to take place in a time period where empires exist.

I had a similar thought, that a game in AoE could really represent a localised skirmish involving people from different empires, rather than an actual simulation of the development of those empires. Which also fits more with the scale of the map.

But the article also says that if you understand what an empire is, then there are empires all the time, and basically all time periods after prehistory would fit the bill.