IQ is a troublesome enough concept without abusing it to claim racial superiority.
Europe only really pulled ahead technically towards the end of the Middle Ages, and the world they found was in many cases ravaged by the very invasions I described. Islamic civilization, for instance, had been devastated by the Mongol invasions; the burning of Baghdad and its fabled library is one of the great crimes of human history.
I suspect, however, that you are referring to China, and its withdrawal after it had initially began exploring the Indian Ocean in the 15th century is a lot more complex than “stagnation”
One thing is clear, writing was not invented in Europe. Agriculture was not invented in Europe. The building of cities, and the entire artifice of urban culture was not invented in Europe. Metalworking was not invented in Europe. Animal husbandry was not invented in Europe. As I said, those core technologies were all invented elsewhere and later imported into Europe.
The Huns collapsed in very short order, and the Mongols created the largest land based empire in history, but they did not penetrate far beyond the Pontic Steppe. Western Europe’s most important powers; France, England, the Italian city states and the German principalities remained free of the invasions that the Middle East, Central Asia, the Subcontinent, and East Asia suffered.
Another factor in pushing Europe forward was the collapse of the Byzantine Empire, which had important ramifications for the Renaissance.
In the end, there is nothing special about “white people”. We’re no better or no worse than anyone else, no smarter, no more gifted, what we are is the beneficiaries of other civilizations’ innovations, and an accident of geography which made Europe a good deal more difficult to invade than many other regions of Eurasia. It also worked in reverse; both Napoleon and Hitler were stymied in their attempts to invade Russia, because those formidable geographic and climactic barriers which protected Western and Central Europe also made invasion the other way all but impossible to sustain, even with Germany’s vast industrial machine.
You look at white people and, I’m sure, see jet planes and computers, and somehow imagine that represents some basic genetic superiority. I look at jet planes and computers and see what amounts to the steady march of technological innovation, which began a few million years ago when our distant ancestors began chipping rocks to make stone blades. And even looking at jet planes and computers, neither would exist without the mathematics developed in the Arab and Indian worlds, and the very writing system used to record these innovations was invented in Canaan 3000 years ago by people you would likely call Palestinian or Syrian, and itself was at least partially based on Egyptian logogramic writing. The Greeks nicked the Phoenician script, and the Romans morphed into the alphabet we largely know today; but neither the Greeks nor the Romans invented the alphabet.
Even the majority of grain crops we grow today, in particular the wheat species, were first bred in Central Asia. Animal husbandry was born there too, and it’s likely the only actual independent development of agriculture was in China, and of course, among some of the Mesoamerican peoples.
So yes, it was white men who invented jets, but without several thousand years worth of technical development, much of it happening outside of Europe, there would be no jets at all. Where you see a divide, I simply see a continuum, the flow of information across the Old World that delivered writing from the Middle East, grains and domesticated animals from Central Asia, iron from East Africa, and glazed pottery possibly from Japan.