You can take it in any direction you want, but I have pretty low expectations of schools willing to teach my kids from 10 to 16, or mechanics willing to fix my car at 20, or doctors willing to take my blood exam at 22 — all that just because that would be convenient for me.

The modern society started with the Industrial Revolution, when the people understood that there are some very tangible benefits when everyone starts working at the same hour, and started building around that. This building included discarding "local time" (an astronomical fact) in favour of standard time (social contract.)