If you go by square miles and by population, you will find Belgium is the most cycling-centric country in the world. A much larger percentage of Belgian population turns pro cyclist than any other country in the world, because there are only 11 million of us. The country is so small that basically every town has its own cycling race. Lots of sports journalism is cycling related. Just like in every other country in the world, news is predominately local or national. That means we get more news about 2nd, even 3rd tier Belgian riders, than 1st tier foreign riders. Please don't try to tell me this is any different in any other country. because i'm quite sure in the UK they will sooner talk about how Leicester City is failing, than they will talk about how PSG is doing. Belgians simply read Belgian news and that simply tends to be about Belgian cyclists first and foremost. This is the only explanation you need to be looking for.
When i talk about certain Belgian riders, i do so because A/ i believe in them (those i talk about) and B/ i can get more information about them a lot sooner and a lot more easily than riders from other countries. I don's speak Danish, i don't speak Spanish, Portuguese or Italian. So in order to get information on young/unknown riders from such countries, it requires a lot more energy or waiting for mainstream English/Dutch media to pick up on those. That's why i knew and believed in Van Aert before this forum ever heard his name, that's why i have been a firm believer in Evenepoel's potential and spoke of such riders before it might have seemed to make sense to non-Belgians on this forum. But i think now they know it did make sense.