There are a lot of different reasons why the people who were interviewed are the way they are; however there are Millennials who majored in useful majors, have good jobs, are married and yes, have at least one child ( I know quite a few who have more than one ), have investments and savings. The same can be said about GenXers.
We are talking about a trend. Trends don’t tell us about individuals, it only tells us about groups. There are lots of millenials who are just as you say, and we need every one of them.