A bachelor's degree takes you three years to complete, and say it consists of about thiry courses, and say each course is based on a book of about four hundred pages (fairly standard for fields like mathematics, physics, computational science, etc).
This could be learned in a month: 30 courses in a month is 1 course a day, or 400 pages a day. If you read for 12 hours a day, you’d need to read 33 pages per hour. Most certainly doable.
Why exactly are degrees several years long when I could self-study it all in a month?
Now I have often heard arguments like this:
A day per topic is not enough to get an in-depth understanding or do exercises or master the topic or be able to pass an exam or complete any decent assignment.
However, a person who obtained their degree quickly forgets most of that anyway. For example, I've had a course in linear algebra. But a person who picks up a linear-algebra book and studies it for twelve hours most definitely will know more about linear algebra by the end of the day than I do currently. Simply because it will be fresh in the memory, while for me, it’s been three years since I had my course in linear algebra.
My point is: Yes, twelve hours a day per course won’t give you a deep understanding, but you’d still know more and be more knowledgable about the topic than a person who actually obtained the degree!