A blog post in Slate the other day states that it is not just young people (i.e., Millennials) who are moving back home, but people of all generations are moving back with parents in increasing numbers. The blog lists several explanations for this, including the increased cost of living as well as the increase in immigrant households where multi-generational living is less taboo than here in the US.
I have worked with a number of families over the years who are concerned that their adult child living at home is a problem. After all, our culture has precious few rights of passage from childhood to adulthood, and becoming independent by moving out of your parent's house is possibly one of the biggest and most important.
It seems that reality is forcing many of us to change how we look at this ancient (it's not so ancient) right of passage. As a Gen-Xer, I might have been part of the one of the last groups to move out of my parent's house and in to an apartment I could afford on a $22K salary (the apartment cost me $450/month, and my electric bill was $7). The 90's were a hectic and magical time.
Just because you're poor (not wealthy), or it simply makes more sense to live at home with your parents, or your culture of origin (or, your parent's culture of origin) concludes that the best path is moving home, or continuing to live at home after 18, that does not mean you should also continue to be a Dependent. A parent once told me a charming story where his daughter, who was pursuing an advanced degree, also got married to her sweetheart. They got an apartment together, but came by the parent's house daily to rummage through the fridge and ask, "What's for dinner." By "marrying off" their daughter, the parents seemed to have gained a son, in the worst sense of the word. These newly-weds were, for all intents and purposes, still Dependents.
When one becomes an adult, regardless one's financial, emotional, cognitive, or most any other conceivable situation, the relationship between the parent and now adult-child, and that adult-child and the household, must change. The adult-child must now take some sort of responsibility for the household, and the relationship between parent and child needs to move in the direction of peer or roommate. It does not have to be an immediate change, but not making that change is going to create tension in the household, and this tension will build and build until something (usually the parent's patience) gives.
This is not to say that the problem is always the "slacker child" who refuses to grow up. In my experience, parents are equally reluctant to start treating their 18 year old more like an adult. The phrase I often hear from the parent is something like, "If you would act like an adult, I'll start treating you like one." The truth is that it is the other way around. For most adult-children to act like adults, they need to first start being treated like one. The burden is usually on the parents to make this shift. They are, after all, the ones usually most equipped to initiate such a change.