If you just want to learn about the theoretical side of things or if your discipline is purely theoretical (maths, etc.), then sure: You can learn from books and online materials, though chances are good it will go wrong in some way.

For instance in a field like maths it can be important to have someone correct you if you got some fundamentals wrong and it is hard to learn how to formulate a proper proof without someone checking and correcting your first attempts. It can be done, it might just take you a lot longer.

Other areas however require labs and expensive equipment for the practical applications. Some skills you can't learn from books alone.

That would be (almost) like saying: You don't need an actual bicycle to learn riding one, just read a book!

A library won't issue you a diploma employers/states would recognize.

He said education, not certification. Education happens in your head, not in a database where you have x qualification or not.

Education via libraries requires dedication and critical thinking; neither is necessary for modern universities.

And many libraries (especially my local city library) have a notable lack of technical books, so you need quite a bit more than dedication and critical thinking if you're going to go that route.