....apple designs and makes their hardware, other companies manufacture it for them.
No they don't. Not really in that way.
That's a bit of a simplistic view, and you know what, I wish it was genuinely like that.
There is no point in Apple trying to re-invent the wheel for every component.
I know they tweak things, and fiddle here and there.
but actually design everything and get others to make it. Not really.
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Does that really matter? It's Apple who design and put things together to create the products that we know and make them arguably superior from the rest of competitors.
Do you really ask who made the brushes and the paint for the drawing you buy? Do you even know who made the brushes and the paint for the Mona Lisa masterpiece? I didn't think so. But the name of the author is immortal.
So yeah... who made the batteries,screen, processor etc for the Appel iPhone? Who gives a toss. Some companies who had to make it good enough it to meet Apple's standards and stay on business, or go home.
I'm not arguing, just brings a little realism to the fantasy some seem to have here.
Car makers do the same, they use other bits already made and have done for years, gearbox's, engines, lights, etc etc.
I think you have it the wrong way round though also.
Apple has, like everyone else has to, as a builder. Use what others have developed. Apple does not DEMAND a 5 year battery.
Other companies design, develop and make batteries, and like you or I, Apple goes shopping to see what's out there and what it can use, albeit on a large scale.
Apple have to accept what's there, it's not as you paint it, made it to Apple's demands or they go elsewhere. Apple is almost a custom PC maker that assembles parts & writes software to glue it together.
there is nothing wrong with that. But they don't have access to magic.