Do you think you can turn these parts into devices at no cost, package them and send them to a store half way round the world at no cost, put them on the shelves and sell them with paying rent for the store, wages to the employees, taxes, a percentage to the bank for handling the money, and no customer will ever call your help line, nobody will ever return a device, no device will ever break and need to be repaired or replaced?
Now if you add all that cost, you arrive at gross margin. Which is not profit, because gross margin doesn't take into account development, marketing, advertising, the cost to run a business and all that.