When it comes to trading there are a lot of things you can learn from books but there are just as many that you cannot learn by any other means but by experiencing them, and the only way to gain this experience is to be part of the market, this is one of the many reasons of why taking a high risk strategy is a mistake, those people lose their money so quickly that the lessons they learned from the market are too few and by the time they comeback they have forgotten most of what they learned anyway, which will make them to repeat the same mistakes over and over again.
This is true, books could be a bit too old fashioned and I do not think that you need books to learn anymore. But online world is filled with stuff that you could learn from. Starting from simple articles, to in depth classes, to youtube videos to courses. You could learn from many of them, and that would replace the books in your saying.
However, the rest is correct, you have to learn from doing things and learning what mistakes you do, which would result with you getting a bit better in the long run. Of course it will take some time before you could get better, but in the end you will learn from your mistakes which is the best teacher.