As it （=slang) does not have to support the weight of literary tradition, it is able to speak of modern things and to draw its metaphors from the most recent inventors. Much of it, fortunately, climbs up gradually into recieved usage. If this were not the case the literary language would become dead, and it would soon be impossible to speak of the modern world in terms that stylists would permit
Source: On proverbs, by Bertrand Russell
More info.: https://russell-j.com/PROVERB.HTM