American family structure for last 50 or so years have been that it is responsibility of the parents to raise the kids till they are adult (18 years old).Most of the kids also felt that the right thing for them to do is that to become independent at that age and most kids were able to get the plentiful jobs available then and others went to colleges and lived away from parents in dorms or housing near colleges. In essence they became independent at times kicking and screaming.
Good thing about this scenario is that they became autonomous adults at this age and took responsibility for their actions including decision making about personal relations as well as financial matters. Alexis De Tocqueville admired American independence(even at much earlier time) particularly of women in his famous book written in 1830's" Democracy in America".For the society with many children this worked well and gave parents and children sense of independence.As parents grew old (if lucky) their were always sibling or some children were there to take care of weak and incapacitate.
Now things are changing.Most people have only one or two children.Life has become much more expensive and expectancy has increased.Even sick people with many health problems can live much longer than they could do before.
In this environment we should look at the living conditions in society and look at how to best preserve family and nations wealth.It is in the interest of the country and individuals that most people stay in their home for most of there life rather than in nursing or assisted living facilities.
So ideal set up is that even the grown children may live with their parents or vice versa.
This can help parents as well as kids( grand parents can be high quality cheap day care providers for their grand children).
This system at superficial inspection may seem regressive.But on thorough examination it may provide higher value to families.
Yes there will have to be adjustments made in parent children privacy issues .Will the kids and parents approve each others dates or mates .For many adjusting and thoughtful souls it may be the solution needed in this time of financial crisis. Only question left is, IS THERE ENOUGH ROOM IN THE HEART.