That's one way to think about numbers and not about the persons.
I believe most of countries have orphanages already -- and what you're suggesting already exists in some countries (I do believe we still have that in Brazil).
While that could increase the number of people, orphanages are not great places to raise a child (with rare exceptions). Imagine you growing up with a large group of other child, and nobody actually take the time to take care of you. What kind of person would you be today?
I believe most of countries have orphanages already -- and what you're suggesting already exists in some countries (I do believe we still have that in Brazil).
While that could increase the number of people, orphanages are not great places to raise a child (with rare exceptions). Imagine you growing up with a large group of other child, and nobody actually take the time to take care of you. What kind of person would you be today?