I hope you realized I meant that GDP per capita. Assuming you did and still think it's high, here's a more detailed estimate:

Let's arbitrarily pick the 10th country from bottom of the GDP per capita list by CIA Factbook: Niger. Now we can make some more concrete statements. On average Niger women have 7 children and presumably raise them on 2*GDP per capita income. This gives 0.28 of the GDP on raising a child. (Infant and childhood death rates seem to be negligible for this calculation, perhaps increasing average spending by 10% when assuming they make it to age 15.) So assuming a high quality education takes three times as much as the typical education/child raising of the time we'd get about 1 GDP per child per year.

Niger happens to also have the highest birth rate in the world. Picking the country above it on the list, Afghanistan, gives a birth rate of 5 children/woman and would give us about 1.2 GDP per child per year. In any case, my 3 * GDP estimate looks rather high here, but on the other hand so was my estimate that all the children so taught would go on to work at Google-equivalent pay scales. I might then round my guess to 1.5 GDP per child per year when including extra costs like PR or administering tests to see who to admit that are done on more children than are educated.

If you think that's still rather high, then you probably disagree with my estimate that such a program would want to spend three times as much money on education and child raising as is standard in the given country.

Aside: how do you make links here that include parentheses in them?