If you think of it like a hick farmer would
OK, let's do that. But we need to use an example where there are two or more outputs under 'joint supply'. Otherwise it's not analogous to the situation with Apple's ecosystem.Let's figure out the profit margin on wool from your sheep farm. Each month:
- Your wool revenue is $1000
- Your mutton revenue is $1000
- Your total costs (feed, labor, etc.) are $1000
What's your profit margin on wool?Most people will try to split the costs 50/50 since revenues are equal, making wool's margin (1000 - 500)/1000 = 50%.
But then ask them: What if wool prices double, so now:
- Wool revenue is $2000
- Mutton revenue is still $1000
- Total costs still $1000
Should wool's costs still be $500? Or should they now be $667 since wool is 2/3 of revenue? The margin would be either: A) (2000 - 500)/2000 = 75%
B) (2000 - 667)/2000 = 67%
Which is right? There's no correct answer, because any cost allocation between wool and mutton is arbitrary. We can calculate the total profit margin for the farm, but not for individual products.