If a lawyer makes two hundred dollars and hour, but he chooses to not work today because he needs to clean his car. If the thought process behind that is saving the $40 dollars from the car wash place, he effectively lost $160 dollars.

This example is not 100% valid.
For someone who's doing intellectual work doing some physical work can be actually a leisure, a way to give your mind a break and generally a healthy thing.
Besides that, you can choose to wash your car instead e.g. mindlessly watching tv or drinking beer - then it's real saving.

But your general advice is correct, I attended HR school and were taught about that every person has a specific price for their free time and in order to successfully employ them your offer must be greater than their value of free time.