I think you may have misunderstood my piece. To be a good poet, you have to learn the proper techniques of poetry. It’s not necessary to learn the proper techniques of music, painting, etc. Each requires its own rules to be learned.
I will say, though, that the best poets could read a number of languages, such as Latin, Greek, German, and French, as well as others. Learning other languages opens you up to new ways of thinking. Painting can also open up new ways of thinking about poetry and music, for example. But that’s a separate article.