It's not impossible, but it's a painstakingly long task to do, and by the time they get it, their interest in the game probably have already died out. Because as it stands, that'll be the sole thing that'll kill the majority of the playerbase. There are people that don't tolerate grind as much as the Koreans do, which is why grindy games are considered negatives.Again, underperforming just because of something you did when you were new, and get severely punished by having to spend a fortune to correct that mistake, or start a new game, is enough to drive players away.
They could implement another method that'll keep it from being too difficult, but not too easy to get. One such way is to get pages from a repeatable quest (which would require some difficult task, probably like endgame content), get enough pages to get a book. This is just one method. I'm sure we all can keep throwing some more.
This is my personal opinion though, at the vert least make the book obtainable one time-only like hitting the cap. By that time they'll have an idea what they want to do, and that's a motivator to play through the postgame stuff with a poor build. But if they want to change their build again, they'll have to work for that book.