I don't have a strong knowledge of Japanese (year in college as part of linguistics degree, wife speaks it), so it's possible I'm mistaken about the nature of it grammatically. But my point isn't to make some Sapir-Whorf / Hopi Time-esque argument about its pragmatics, just to argue a point about the grammatical structure (whether the future tense is grammaticalized or not). That point might not hit exactly with Japanese if there's more grammaticalization of the future tense in Japanese than I thought, but my point is regardless to compare a language like English that has a grammaticalized future tense via auxiliary verb to languages that don't grammaticalize future tense.

To be clear, I completely disagree with the Sapir-Whorf hypothesis & don't think there's anything "weird" about Japanese, the past / nonpast split as opposed to past / present / future is quite common cross-linguistically[1]. The idea of whether something is grammaticalized is separate than whether a language can express it -- AFAIK the current theory is that all languages express just about the same set of concepts, just certain languages evolve grammaticalizations of tenses, aspects, topic, politeness, etc. and others represent them "ad hoc" via constructs like "do tomorrow" etc. Hopefully that makes sense. I find the "Mysterious Japanese mind" trope orientalist and stupid.

[1]: And there are lots of systems, like multiple levels of past remoteness, too: https://wals.info/feature/66A#2/26.7/149.2