The hardest task in a foreign language, even harder than talking on the phone, is reading books in that language. Even many long-term residents of a country never read books in the language of their adopted country, no matter how well they speak the language. In this sense, a person can live 50 years in a country and not become completely bilingual.
There are many good reasons for this attitude to foreign language books. Many people read at night in bed. This activity is supposed to be pleasurable and relaxing. Straining your brain and using a dictionary are definitely not fun and restful. Also, the learning curve for reading is very long and steep. In other words, it takes a lot of practice before you can read a book in a foreign language as easily as in your mother tongue. Finally, depending on your native tongue, there may be plenty of reading material available as is. For example, if English speakers have no problem finding reading material wherever they are. There are always English books in libraries and second-hand stores, not mention English books in retail book stores. Therefore, it is clearly very easy not to avoid reading foreign language.
However, if you ever really want to master a language, whether you live in a country that speaks that language or not, you have to read it all the time. Passively but effectively, reading a book in the language adds vocabulary, understanding, and nuance. You see many words than you will never hear. Moreover, over time, the reader intuitively understands what they mean without looking at a dictionary. Differences between similar words suddenly become much clearer and easier to remember after you have seen them used hundreds of times. You learn like a native. Also, the connotations of words sink in without any formal explanation.
To reach this stage is like climbing a tall mountain. The first part of the journey is hard and tiring, not to mention frustrating at times. However, when a language learner reaches the peak, effortless reading of a foreign language, it all seems worthwhile. You can understand Goethe, Zola, and Orwell in the original, or anybody else who wrote in that language. That is a natural high, like climbing a mountain. However, unlike Sir Hillary, you never have to go down. You can enjoy the view all of your life. That's a good reason to learn how to read in a foreign language.