Or should that be linguist? Etymologist? I'm not sure of the proper term here.
While writing exams I've had episodes of Magnum P.I. playing on Netflix in the background. For those of you who have never seen it (I'm looking at my students, here), it's a good but goofy 1980s detective show, set in Hawaii, starring Tom Selleck. If you can put up with bad 1980s action music, it's worth watching.
In this particular episode Thomas Magnum is pursuing a cat burglar while working as a hotel detective. He gives the following monologue, which I recall enjoying when I last saw this episode years ago (I forgot all about the story and such, but I remember this bit):
I didn't think the cat-man's taunting note was the height of subtlety, either. And I guess neither is that old adage about killing two birds with one stone. But the reason clichés are clichés is because ultimately, they're either true, or they work. That's why you never hear sayings you've never heard before. Those are the ones that didn't work. Which is all to say why I was hoping this one would.
This is some fun evolutionary reasoning. On the other hand, what are we to make of contradictory clichés, such as "many hands make light work" and "too many cooks spoil the stew"? Presumably we are to balance the two, finding the point where Marginal Revenue Product equals Marginal Factor Cost. I suppose MRP=MFC isn't very pithy.