I think it's pretty clear. They sold more phones than they had stock available and now are rushing to fulfill their orders (considering they said this would happen it shouldn't be surprising).
As far as why some get their's sooner? It's all based on color, size, and storage. Some people ordered sooner, some people ordered less in demand combinations. Then they had to ship at least some to stores as having a store presence is important, that they didn't reserve pluses at launch for this is frankly amazing to me.
Also take a deep breath, take a step back, and remember that today the 7 has been out for ONE WEEK. No one is doing to have their lives ruined because it took a few extra days to get a phone.
I can relate to your feelings.
Every YT channel has all colours and models available just to put them in a plastic bag with some keys.
It really is a sign of decadence and doesn't shed a good light on our society.
Seriously? People watch the reviews, that's it. Taking a piece of technology that absolutely no one in the world NEEDS and ruining it shows nothing about society except that people are interested in how it holds up. When we see videos of people wasting tons and tons of food for the hell of it or killing animals for no reason or something then it'll be a problem.
I'd say getting upset about having to wait a few days for that tech shows more about society than videos showing them get scratched.