> The practice was probably used to improve the children’s chances of securing a university place.
The fact the competition to get into a university is so hard you need to co-author a scientific paper for this is the problem. Education should be accessible for everybody.
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!
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.
The fact the competition to get into a university is so hard you need to co-author a scientific paper for this is the problem. Education should be accessible for everybody.