Beyond the factual errors, there are numerous unsubstantiated claims. I don't know how one would come up with an objective way to measure philosophy and poetry. How much philosophy and poetry from (for example) the Kushan Empire has survived? What's the background for the claim that its philosophy and poetry dwarfed the Roman Empire's?
The idea that we should pay more attention to many of the other polities in history is a valid one. But I don't think an article filled with errors and baseless claims is terribly useful.