Why can't we Japanese speak English well

Reading English sentences, most Japanese people try to translate them in Japanese in their head first, and the processing takes a long time. That is considered a bad habit in learning another language. 

In a Japanese school, the majority of teachers teaching English can not grammatically explain English sentences in English, for instance, not "This is subject" but "これは主語です". Do you think this manifests the problem that Japanese people can not speak the language, even though they have studied it for over 6 years in school?

In Meji era, about 130 years ago, there were people who were able to speak and write English accurately. Inazo Nitobe, who published the book "BUSHIDO: the soul of Japan" which is written about the Japanese spirits in English; something like a Japanese bible to introduce Japan all over the world. Okakura Tenshin, who introduced the Japanese traditional culture all over the world by writing a book in English, the book is called "The book of tea". Each of their English books were written accurately and perfectly that a native speakers mistook it for an American's work. Needless to say, both of them, of course, were able to speak English fluently. They went to an English school and learned the language under an American teacher. Hence, the class was conducted in English, not in Japanese. 

Nowadays, there are so many materials and opportunities to learn English in the range of its books to online Eikai-wa (英会話) and English-learning sites. But still, a lot of Japanese students have a difficulty when it comes to English. I assume that it is sort of linked to the development of technology, in short, the more technology develop, the lazier people become. It either makes people's lives more convenient and sophisticated or makes people feel lethargic. People seem to have gotten those environments. Something good has its side effect as a medicine. The side effect of the technology development is that people crave more of instant gratification, wanting a result readily. They seems more impatient getting temper and stopping to be deep thinkers Such an impatience definitely affects your habits, life and even leanings. 

Giving a lesson to Japanese students in English is probably one of the elements to boost their English skills. However, the problem with their English is more radical one. Why were Inazo Nitobe and Tenshin Okakura able to master English up to the level of native speakers without sufficient material related to English? It is because they were extremely eager to learning the language, and dedicated themselves to do so. Inazo Nitobe read up on an English bible over and over again that was the only way to learn English back then. He read all kinds of books available in a library as more English books were imported to Japan. Acquiring another language is a long journey. If people can not get the result, they give up right away. 

If I had interviewed Inazo Nitobe and Tenshin Okakura regarding how to master English, they would have answered, "It is depends on individual's effort".