A "free stuff" is incompatible with unlimited fertility. The bargain has to be that the necessities of life are provided only if you agree to limit yourself to

A "free stuff" is incompatible with unlimited fertility. The bargain has to be that the necessities of life are provided only if you agree to limit yourself to replacement fertility. If we allow unlimited fertility, then no matter the starting conditions, any group that breeds faster than the rest will come to dominate the whole population.