> software engineering jobs in Japan are often at either larger multinational companies or companies with enough presence outside of Japan that they have teams which are in English.

Just because you work in a multinational company where they have English speaking teams does not mean that you should not know the language. It is weird to assume that just because your first job is with an English speaking team you will always work with those teams or in that company at all.

What about daily life? Communication is a fundamental part of your activity as a civilian imo. Not understanding what is going on in a country without using some device to translate for you is not acceptable. Whether in a train or during an earthquake you must always be able to communicate.