Because its for airplanes, up in the air, with hundreds of people on them, sitting on thousands of gallons of jet fuel hurtling through the atmosphere over a densely populated area near you.
Regarding Note #4, I've noticed that the Qty=10 number seems to hold true, maybe its closer to 7. I also think it scales in organizations. How many industries are dominated by 5 to 10 players? Aerospace, Automobiles, Banking, Media are a few that come to mind right away. To bring it back to interpersonal communications, I can manage about 7 people very effectively, when I get much beyond that I starting thinking about someone running interference for me. If I knew anything about the way military organization works, or had ever taken a college level management course, I'd know how I'm stating some rule of thumb most everyone but me knows about already. I do enjoy reading your essays Paul.
I am probably misconstruing things, as I often do and being simple-minded on top of that, but this seems like a circle-jerk and makes me wonder what happened to Tim Berners-Lee's musings about the Semantic Web, and why search hasn't progressed in that direction in some exponentially powerful and revolutionary way.
I started out accepting credit cards, then added PayPal. Sales increased 6%. Granted, this was back in about 2006, but there are some people who won't buy unless they can use PayPal (and US Postal Service).