I always had a feeling if Apple ever had any market dominance they would use their power to destroy competition. Reality is Apple is worse than Microsoft with regards to being anti-competitive and it shows big time!
Conjecture.
Microsoft has been found guilty of abusing their monopoly plenty of times by courts in many countries. I'm still waiting for a similar ruling for Apple.
Microsoft entirely owns the worldwide markets for computer operating systems and office suites, and hell, they are scraping every last penny out of them. While the ASP for computers has fallen dramatically during the last 10-15 years, the ASP for Windows has actually gone up. Which means Microsoft's share of profit per computer sold has risen astronomically over this period, while PC makers are struggling.
Talking about ways to shut out the competition... Microsoft has a long history of it. For instance, they had made deals with all major PC makers that forced them to pay Microsoft for every PC that they sold, no matter if there was Windows on them or not. This way, no one ever thought about putting any other OS on their machines, and it also kept other OSes to gain any traction, because they were only available on noname computers.
And just like any bar can switch from Coke to Pepsi, Pegatron has the choice to switch over to Asus and say goodbye to Apple. Or, alternatively, Asus can have their computers produced somewhere else. There was no such choice for OSes and PC makers at that time.
Oh, but people forget so quickly, and suddenly someone else is 'worse' without even playing the same league of corporate fouls.
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In this case, if Apple prevents ASUS from building computers, then I, as a customer, lose the ability to look at both products and make a decision and buy the one that is better, because one is not for sale. Therefore, no competition. Therefore, anti-competitive.
Is that so...

Truth is, Asus can go to any other of the huge manufacturers (Compal, Foxtron), or even build the computers themselves if they really want to.
This is called BUSINESS. Try ordering a Coke in a Pepsi bar. Does it kill Coke? Of course not. But poor little Asus, selling more than twice as many computers, is being bullied by big Apple.