Doesn't even have to be profit driven. If the government (or anyone with sufficient $ / technical skill) either owns or co-erces the CAs in the current model, you're boned.
It cuts costs in various ways. As you say, it cuts the cost of your supply chain. And it does add up. You go from 1 colour to 2, and you have doubled your inventory tracking costs. If you're going to different chassis builds (as per samsung and the rest), then you're massively increasing costs to re-tool the factory, keep track of a whole inventory of other components for the manufacturing, etc.
It most definitely adds up, and this is why apple can do stuff like maintain 45% margins on the macbook air whilst keeping the build quality of the enclosure, fund OS X development, NOT include shitware, provide iCloud and all the other support, while the PC guys can barely clone it somewhat without providing any of the additional service/software stuff - on margins so thin that most of them are posting losses or otherwise not doing well.
HP/Dell are completely insane with the configuration options you can do on their notebooks. For example, I can select whether or not to include a $5 option analog modem on our corp issued laptops. I can select multiple different WIFI cards, I can select a heap of different screens, etc. The number of different combinations that were possible with our Elitebook 8570s for example was simply huge.
Now because HP offer so many different options on that same model that really don't matter - they can't stamp out a few million of them in case people want something tweaked. They can't order bulk on CPUs in case people don't order that CPU. Etc.
Apple? Here are 3 different sizes, each has 2 different CPU/RAM options. We offer a custom build ultra high end option for bumping the CPU/RAM.
95% of sales they can fill with machines they can just stamp out en-mass.
You get logs on the Mac and plenty of diagnostic tools including dtrace. If the phone is broken you take it back to apple and they give you a new one, but there are diagnostic logs on that too that you can get off it.
Sounds like you're a typical nerd who gets asked to support apple gear and you're out of your depth, so just say "it's crap" because you don't understand it.
"Just think, with VLSI we can have 100 ENIACS on a chip!" -- Alan Perlis