You can very easily become better than 99% of humanity at a topic by diligently working through an advanced textbook. That’s not genuine expertise but it’s not

You can very easily become better than 99% of humanity at a topic by diligently working through an advanced textbook. That’s not genuine expertise but it’s not nothing. A community of practice is necessary for true expertise in mature fields but you can get a long, long way with a series of textbooks.