Because there is a concentration of smart and ambitious people. For example, Russia annually loses 2% of scientists who go abroad, and the United States receives 700,000 new scientists every year. Simple arithmetic. Everything is obvious.
In fact, this statement is not true. Technological discoveries are being made in North America and Europe, as well as in Japan and Korea. Often, discoveries that were formally made under the auspices of Western companies were actually made in research centers in other regions. From this we can conclude that breakthroughs in the technological field are made where money is invested in it, where there is a certain tradition of research activity, a base from which one can build on. If a component is missing, the result is reduced. Most often, it is precisely funding that is lacking, which is why research centers and development companies are absorbed by Western corporations.