Yeah, nah - that "we" doesn't cover all the other calendars also in use.
The Julian period is a chronological interval of 7980 years, derived from three multi-year cycles: the indiction, solar, and lunar cycles. The last year that was simultaneously the beginning of all three cycles was 4713 BC (−4712), so that is year 1 of the current Julian period, making AD 2026 year 6739 of that Period.
> Even if one day humans have to account for relativity in their commute
You don't think there aren't already application domains that have to account for relativity differences between reference frames?