I know that no one (well, hopefully no one, but someone probably does) believes that money really does grow like shiny green leaves on a tree, it's the root of the matter that is the issue. Rephrased, the saying could say, "Money does not sprout from nothing."
Like a government handout, but from parents instead of Big Brother.
Because little Johnny didn't have to work for the money he received, wouldn't it would be counter intuitive for him to think that income is (normally) proceeded by work, and is therefore the product thereof? I tend to think so.
My brothers and I never received "government handouts" from our parents (which are often masked as allowances) growing up. Very early on my parents would find ways for us to earn money to finances our extraneous spending, like mowing, special cleaning, selling things, and yard work, and for that I will be eternally grateful.
Don't raise your kids to expect money that they didn't earn. It won't stop just because they grow up. There's a reason 47,000,000[source] (that's million) Americans or on food stamps (i.e. government allowance).
Thanks Dad and Mom!!