If you cut out the commute, obsession with socializing, 1x speed inefficient lectures, impersonal general purpose homework, breadth first class catalog that try to get you well rounded - the necessary material for most professionals is not four years worth. "I never use what we learned at school, professional life is very different" is a very old meme.

Where I live, colleges prepare you to be able to choose to be many things - continue academia, or be part of the workforce under diverging titles. They assume you don't know what you want to be yet - and it is mostly true. But if you are at a point in life where you know what you want to be, you can skip most of it (or even do it live when needed). The "keep your options open" attitude of colleges have a lot of overhead. What most people need from a 4 year college can be easily condensed into a year. It WON'T be 4 years worth of material. But if you know what you want (not keeping your options open) you don't need most of it.