This is a question you could ask in any sport, not just F1. Almost half of the worlds population is located in India and China. So statistically, 10 out of 20 best athletes in any sport should come from those two countries and they should be near the top in any sport. However, we know it is not like that and they are successful in very few sports.
That's because, to become great in any sport, it is not enough just to have the talent, you also need to have the interest and opportunity. Why are Brazil, Germany, Italy always among the best in football? Are they so lucky that best footballers are always born in those countries? No, but football is very popular there, a lot of young boys dream of becoming new Pele, Kahn, Roberto Baggio and therefore start practicing football at a young age. And due to the high interest, there are a lot of youth football clubs and scouts watching those kids. And out of tens of thousands of kids every year, a very few actually have what it takes to become a top footballer. And a lot more are good enough to become a professional footballer in first, second or third league.
I would argue that right now in the world, there are more than 20 people who, if they had the same upbringing as Max Verstappen, would be even better drivers than him. Only, one of those people was born in rural China and will spend his entire life in the circle 10 km from where he was born, one was born in the USA and dreamed of becoming new Michael Jordan and therefore started playing basketball as a kid, one had no opportunity nor interest to go into racing and became software developer etc.