What are you talking about?
EVERY Scientist on EVERY WORLD is building his knowledge and science on knowledge of others, on already known knowledge. Claiming this would mean he isnt smarter is just... dumb. You also have access to all books about science, still you are not the biggest scientest of the world right now. Same goes for the world of One Piece.
His DF is pretty supportive here, but doesnt mean shit if he would be still the smartest or at least one of the smartest persons of the world.
Like the first thing in a university to learn is: "Nobody cares if you know anything, the key is to know where to find the knowledge and how to work with it." Thats the first the most professors tell you when you go for studying. So Vegapunk has a headsup about using his knowledge, since it takes him less time to get the infos he needs at one point, but thats it. Every other scientist of the world could simply to the same, by picking up the right books and would just take a few minutes longer.