No. Samsung "we make aluminium" can't sell to Samsung "we need aluminium" cheaper than it would to other companies. It's the exact same price.
You do. I'm not criticizing you. I'm criticizing AMD. And you're defending them like if you were a part of the family. Also you fail to acknowledge that AMD could in fact be a failed company on its road to collapse. Or the fact that their approach to Spectre / Meltdown isn't perfect. Yes, I prefer Intel products and business culture. And I have no problem with admitting that Intel's strategy is optimized for profit and it has a history of some not very praiseworthy activities. Well... it's business.
Just a list of "no"s. Sorry.
1) No, Samsung is not self sustainable. They would have to join all subsidiaries, which would result in a mess (I don't even think it's possible).
2) No, margins aren't larger. They sell for the same price.
3) And, most importantly, NO, there is no explicit "parent company". There's a net of dependencies, which usually results in Lee family controlling each company. But they can't decide on their own.
For example: Lee family members and other Samsung companies have 25% of Samsung Electronics, so they're in full control in stable times, but if they were going too far, the rest of investors could easily oppose them. And of course Lee's don't control 100% these other S. companies, but they have enough votes to be able to choose the representative for Samsung Electronics general meetings. That's how a conglomerate works.
I've found a graph from 2014 (a simplified version: only the major companies and share percentages are displayed).