I'm sure there are, but it's kind of standard that most 18-21 year olds have only 1-2 years experience in an independent apartment/house. Just like 17 year olds typically only have 1 year experience driving.

I wouldn't even rule it out entirely, you'd just need references (a decent rating).

The same age group is faced with similar problems renting apartments because they often lack credit ratings and previous references.

For many purposes it would be cost prohibitive to run detailed background checks on individuals to discover every relevant fact like that, so they rely on aggregates, which works well enough.