Is it difficult to survive in English while traveling in Japan?
It really depends on where you go in Japan, but in general, you may encounter difficulties to some extent if you only speak English while traveling in Japan. Especially, if you are outside of central parts of Tokyo you may want to do some research ahead of time as to where you want to go and how you can get to a destination. You can also use google translate or other translation apps to ask questions to locals when you get lost. Especially in countryside of Japan, people may get agitated if you only speak to them in English so I would highly recommend to learn some easy phrases such as “Where is ~?”, “How to get to ~?” “How much is ~?”, etc. in Japanese. People here in Japan are mostly friendly and are willing to help foreign visitors if they are in trouble.
Why Japanese people don’t speak good English in general?
I would say that is because we have very limited opportunities to speak in English while living in Japan. Our official language is Japanese, of course and we hardly speak in English at school or at work if you work for Japanese company. Basically, we can survive without speaking in English in Japan. However, we do learn English at school. In fact, these days, children start learning English as soon as they enter elementary school, which continues until they are in high school. The entrance exam to universities normally include English subject which can be at a highly-advanced level if you are applying for top schools in Japan. Yes, we know advanced English grammar, in general. We just don’t have much chance to use it in practice.
All you need is a bit of patience when speaking in English with Japanese people. Most of the time, we do understand if native speakers speak English clearly and slowly.