In the Looney Tunes cartoon “The Weakly Reporter” a group of gangsters break into a jewelery store and steal the alarm clock. Why? Were mechanical clocks really that expensive?
Mechanical alarm clocks were always getting busted up in silent movies, so my guess is simply that the joke is that the bungling robbers stole the least expensive item in the store.
The entire cartoon is a satirical commentary on shortages caused by World War II.
The joke is that alarm clocks have become so scarce that they are more precious than money or jewelry.
Now, why alarm clocks were scarce, I don’t know. Perhaps because they were made in Europe? Or factories were given over to bomb-making? Or the component parts or materials were needed for the war effort?
Ah, here we go: