Well, I guess what I mean is that most people have some level of general intelligence that when applied correctly can generally give good results in most subjects. In general the people who do well in school do well in everything, even if they have a preference, and as such could do well in most of those subjects if they went on to further study. The evidence tends to be that in lower income countries people push towards subjects more likely to bring financial stability than those they prefer which bears this out somewhat.
There are some extreme cases of course but I’m not sure the general public needs to worry too much about those, most of us aren’t an Einstein nor do we have learning disabilities.
The extreme case does not imply a binary scenario ie that there are those that can those that cannot.
Rather, learning ability is a continuum. people have varying degrees of ability to learn mathematics. Couple this with environmental factors and society generates a huge variability in mathematical ability that crosses income levels and other demographics.
This view is rejected by many because it is against the push for equality.