It's not hard to understand; I simply think it is not true.
You said:
"...ultimately the cost price will consist of labor costs, profits and taxes. Even the cost price of raw materials is also made up of this..."
There are innumerable costs you are not considering. I offered a
short list here.
Your ladder to reach the bananas is an expense. As is your basket to put them in and your bananas bin where you keep your supply for customers to browse. You ranspartionb to deliver the banana to your customer. Your banana farm is an expense. Your banana cleaning equipment. The sign over your farm had to come from somewhere. The water you irrigate with. The pesticides. Your signs and flyers to advertize that you sell bananas, your fire insurance, etc. etc. etc.
Also: The how-to book - to learn why your business failed because you climbed a
palm tree ... looking for
bananas.