I think family in very important in society, but I think even if a family is functioning well, whether they are a "nuclear" family, or a family made up of different types of members, in a "deteriorating social and economic environment
Yes, "the family is the most important unit of society and plays an essential role in fulfilling the emotional and physical needs of individuals, which is required for achieving economic and social development". But for a family to succeed, it doesn't necessarily need to be a "nuclear" family, it needs support in caring for it's family. If a society is at war, is suffering severe weather such as droughts, is made up of people living primarily in poverty, is a society with a high illiteracy rate, or is experiencing overwhelming negative health conditions such as AIDS, of course any family will be negatively affected.
Today, the majority of US children are not brought up in a "nuclear" family; that does not mean that these families are bad, they are just different. What upsets many children and young adults are the loss of a parent, whether it is through death, illness, or divorce. But just because these families are different, doesn't mean that they can't provide the emotional and physical needs children need to be healthy children and adults, so they can contribute positively to their society. Children in single-parent families do not suffer emotionally and behaviorally any differently than two-parent families. The article "Confronting the Myths of Single Parenting" below addresses many of the stereotypes people have about single parent vs single-parent households:
A family provides the safety net for their children, so they can be fed, clothed, sheltered, educated, and loved. It doesn't matter what the make-up is of the family, it matters if they are supported in their efforts to protect and nourish their children.
Without a family, children can be hungry, malnourished, homeless, illiterate, and unloved.