I have 20 yr horizon and won't take out money for next 20 years no matter what. Does that mean that for my case, a 2 fund portfolio *( a domestic stock "total market" index fund + an international stock "total market" index fund)* would give better return than a 3 fund portfolio *( a domestic stock "total market" index fund + an international stock "total market" index fund + a bond "total market" index fund)*