I don't think that anyone has said that university is for everyone, although I keep hearing people saying that it is said .
For a lot of young people it is a safe and useful way to bridge the gap between adolescence and adulthood, whilst broadening their horizons and learning more about a subject that interests them. Some will struggle, whether socially or academically, but others will have the best time of their lives, and build a strong foundation for adult life.
To do that, they need to be reasonably confident before going, and be prepared to make an effort to move outside of their comfort zone, which can be difficult, as moving away from home is out of the comfort zone for most 18 year olds anyway.
I found that often the students who waited a year or two before starting their courses did well, as they had grown up a bit, and had a better idea of what their priorities were before starting their studies. Having a bit of a nest-egg behind them after working for a while could also mean that they needed to work fewer hours, which also makes a difference to both social and academic success.
I also really object to degrees being called 'pieces of paper'. The certificates are pieces of paper, but they represent years of study at a relatively high standard, which has been graded by experts in the field. They take a lot of work, and it is very disrespectful to the young people who have gained them to write them off in that way.
A lot of people don't 'use' their degrees in the sense that they don't go on to work in the field that they have studied; but the transferable skills they gain at university (teamwork, leadership, research, critical thinking, meeting deadlines etc etc) make them employable and perhaps more likely to be chosen for 'sideways moves' into well-paid jobs.
Of course, some people can manage without degrees, and go on to be successful in all sorts of ways. That doesn't mean that those who have them are not 'smart and hard working', though. There is a huge logical flaw in that implication.