you're both partially write IMHO.
While apple isn't the owner of pegatron, and therefore not directly responsible for the way Pegatron operates, Apple is Pegatron's (and other factories) largest purchaser. Apple's constant business ethics of Mandatory profit margins, and low balling vendors in a race for the cheapest, they have been part of the problem that encourages and endorses this sort of behaviour by their vendors.
The Vendors, in order to maintain their cheapness and cost effectiveness, which Apple and many others desires so much, have to operate with these ridiculous hours and wages for employees. it is the only way many of these companies can come even close to a winning bid. If suppliers were willing to pay contracts that were more in the "living wages" area, designed so that there's enough money involved that the suppliers can put in proper standards, these factories could hire more people, reduce hours people have to work and increase wages.
of course, then you might as well move production back home, and help our own economies out... but that doesn't please Stock holders. so we continue to perpetuate the overseas cheap labour situation in order to maximize those profits at the cost of those working there.
Your reasoning through profit margins is flawed. I can also argue that those cheap manufacturers sell dirt cheap Android devices. In order to survive they have to suppress wages and require ridiculous hours, etc.
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Imagine if they simply made their products here and decided it was OK make less money. We would have good paying jobs and good products, but wouldn't be maximizing profits.
So more of the people that buy your products would be able to afford more of them.
This is the most stupid thoughts from people that do not understand how US works. Apple profits translate to high stock prices and high market value. These are wealths shared by millions of Americans through stock ownership and mutual funds. If Apple profits are greatly reduced through domestic manufacturing, enormous money will be lost.