This is all assuming that the purpose of education is to get a high paying job.
In the old days, when formal college education was invented, to get a doctorate meant that you were well versed in all areas of human knowledge.
A Doctor of philosophy would be expected to understand the physical sciences, art, literature, philosophy, mathematics, maybe even a couple foreign languages.
The point of education is to learn, and be a more well-rounded person.
To understand the world around you on all its many levels.
This is necessary not just to get an interesting job, but to be a responsible citizen (you can't make informed decisions on who or what to vote for if you don't understand the context of the issues being debated), to make smart personal choices in everything to consumer purchases to health care, and even just to know when something someone is telling you or something you read is a load of BS.
Of course its possible to learn everything they teach in school on one's own, but very few have the discipline it would take to get all of the concentrated knowledge on such disparate fields as you need to get an associates degree in liberal arts in just 2 years.
Unfortunately, the higher you go, instead of learning more about the world at large and getting more well rounded knowledge and understanding, the modern world makes education more and more specialized, so that in the end many of the most educated people seem to have as much trouble seeing the "big picture" as people with no education at all! :(