Why Does The Week Exist?

William Deresiewicz rails against the 7-day period, the only measure of time "that’s not connected to the movements of the sun or moon":

Just consider the feelings the words arouse. Day: nothing much, except a little bit of hopefulness, maybe. Week: dread, languor, tedium, woe. Yes, we sometimes speak about making it through the day, if we’re having a bad one, but as Erma Bombeck knew, we always speak about making it through the week. Despite the etymology of the word, it is the week, and not the day, that has become the repository of the quotidian: of triviality, of drudgery, of routine. Days differ; weeks are always the same. Days begin with dawn; weeks begin with Monday.