10k years is symbolically just for a very long time. It is not meant to be taken literally.
In fact, the term myriad means literally 10 000 in ancient Greek, yet today only its indirect meaning for a very large number remained. We often read in Greek epics about 10 000 warriors. What the authors want to say is just that there are a lot, not actually 10 000.
Chinese does the same as their numerical system is 10 000 based.
In various
East Asian languages such as
Chinese,
Japanese,
Korean, and
Vietnamese, the phrase "
Wànsuì", "
Banzai", "
Manse", and "
Vạn tuế", respectively, literally meaning "
myriad years" is used to wish long life, and is typically translated as "
Long live" in English. The phrase originated in
ancient China as an expression used to wish long life to the
emperor. Due to the historical political and cultural influence of
Chinese culture on the
East Asian cultural sphere, in the area, and in particular of the
Classical Chinese language, cognates with similar meanings and usage patterns have appeared in many
East Asian languages and Vietnamese. In some countries, this phrase is mundanely used when expressing feeling of triumph, typically shouted by crowds.