Singapore's unemployment statistic only counts people who are looking, not people who are retired or have given up [1]:
> A person is considered unemployed if he or she is:
> • not working;
> • actively seeking work; and
> • available for work
I don't know if the other countries follow the same methodology.
[1] https://stats.mom.gov.sg/iMAS_PdfLibrary/mrsd_qtlmr182_Techn...
The vast majority of old people working these jobs, e.g. construction site security, do so because they would likely starve without it.
I don't think taxi driving in Tokyo is one of them (because, as noted, the qualifications needed are pretty minimal), although eg bus drivers are in extremely short supply.