> There's not much taught in a college class that can't be learned from books.
Yes, but how do you know which books, and which chapters, and who do you get clarifications from, and what projects do you undertake to get beyond book knowledge, and what tools (labs, software, specimen, etc) do you use, and who struggles thru the learning with you providing mutual support, and what group do you discuss literature and philosophy with, and who provides expert perspective, where do you find a community of fellow scholars, and how do you evaluate your progress, and how do you signal to the job marketplace at large that you've acquired some skills and are capable of holding a professional position?
You might be able to figure out or stumble upon some of these answers (hard to do since you're starting from a position where you don't know much), but a University can answer all of them.