This seems to be correct or at least correlative but it doesn’t explain Rome.
The Romans’ and Greeks’ technological and cultural achievements, as well as those of the Chinese and whoever, are admirable to the extent that they represented progress up to a point. But the heathen barbarism was always there, as it still is in much of Chinese life under that Godless regime today.
One can of course point, as leftists always do, to the sins of supposedly Christian conquerers and governments over the centuries, however a good standard to use is the old “you know a tree by its fruit.”
God works in mysterious ways, and can do anything He desires. Christ could have personally visited every burgeoning civilization, but for some reason, did not. God could have given the Word made Flesh to each and every culture independently, but did not.
Mark 16:15-16 makes it pretty clear that Christianity was intended to be spread by believers and we were expected to do some of the heavy lifting in spreading the message. It is my pet theory that with this intent, God allowed Rome to develop precisely because Rome's infrastructure, road networks and technology were needed for the early believers to spread the word throughout the known world. When asked why Christ didn't come earlier than He did, I suspect the answer is that we (as humanity) weren't ready to spread His message as fully and completely as we otherwise might.
IMO, blacks as a group have never been at the forefront of anything, except providing a pool of slaves for other peoples. The ones that have done well have allowed themselves to be westernized and have joined civilized people. The inner city blacks such as the ones in Ferguson are no more civilized than the Gauls and Celts the Romans encountered, or the American Indians that early sttlers encountered here. They've been exposed to Christianity for centuries and still are in dead last on the civilized scale.