No, I am very far from agreeing with you. I am saying that if you keep all other conditions the same, you will still see vast differences in the ease of understanding mathematics. This is borne out both by science - there is strong consensus that intelligence is highly heritable, and everybody's experience.
So even if we limit "aptitude" to a strictly genetic sense, it will still explain most of the difference in math ability at 7. All other factors related to growing up will add up to less than half of that.
Regarding practice compensating for genetics, I am not talking about having more supportive parents or more demanding pre-school, I am talking about Asian level hardcore drilling. That can certainly make up for most of the difference, at least when it comes to basic mathematics. But that means that the concepts that a child with math aptitude will pick up in 5 minutes will take 5 hours of drilling for another child.
So even if we limit "aptitude" to a strictly genetic sense, it will still explain most of the difference in math ability at 7. All other factors related to growing up will add up to less than half of that.
Regarding practice compensating for genetics, I am not talking about having more supportive parents or more demanding pre-school, I am talking about Asian level hardcore drilling. That can certainly make up for most of the difference, at least when it comes to basic mathematics. But that means that the concepts that a child with math aptitude will pick up in 5 minutes will take 5 hours of drilling for another child.