It might be a cultural-ideological reason that you think this way. Not every place in the world has those same assumptions and taboos. There are more blank slateist cultures where the only polite thing is to assume that any child can become anything. In other places people take it for granted that there are differences in abilities, talents, aptitudes, personalities that are fairly clear by age 10. In the US, this topic is too similar to how racists talk about blacks, so the whole thing is taboo. In places where the topic of innate talent does not have racial connotations (more homogeneous countries), people more readily accept it.