People in European countries where renting is more common than in Australia don't pine for housing when they have families. They have more security in the properties they are renting.
I have family who rent in Copenhagen and in Paris, and they have been renting the same properties for as long as I've been alive - there is no tension that the rent will become so high that they have to move and no thought at all that the property may be sold and they be turfed out.
So do people rent for longer because longer term rental contracts exist, or do longer term rental contracts exist because people want to rent for longer? Conversely, do people in Australia prefer to buy rather than rent because of shorter term rental contracts, or do shorter term contracts exist to accomodate the fact that people prefer to buy?
I'm more talking specifically about australia. It doesn't make sense to think that the wants / needs of a teenager would be the same as a person in their 20s, and a person in their 30s.