Why do young people become independent later?

A few years ago young people left home when they were younger, or to get married or to go to work. 
I think that they had a life very different from nowadays, because they left home and I think that they were mature comparied to now. 
Also, the majority of people had children younger because they it was easier, most people worked when they were teenagers to help the family because the majority of people had a family business or they worked in the country. 
In the past, was much easier find a job, because there was much less unemployment, on the other hand in nowadays there are a lot of problems to find a job because the people have to have a lot of studies and to have a good job it is more difficult. 
In my opinion, I think that in the past people were quite mature because for twenty years they had a family and therefore there were more responsibles, on the other hand nowadays of theenegers when are twenty years old they only think of parties and they are not responsible. 
Also the other problem is that nowadays there is a lot of crisis and the majority of young people don't leave home because they can't find work.