What is maybe less clear is the benefit of extending formal academic education to 18 and beyond for everyone. If someone is not academically gifted, why make them waste years of their life struggling through an academic education. What's the point?
The relationship between education and achievement for a given person probably follows an S curve. More education has an impact in the steep part of the slope, but eventually the limiting factor is natural ability, and achievement flatlines. The problem with education today is that people looked at that curve when it was in the steep part, thought "more education means better outcomes" and just kept blindly throwing education at people.
Most people would be far better served by vocational learning after a certain point. Effectively every career is a form of vocational learning, we've just delayed it further and further in the name of academic education which has limited benefit.