This new "Points of Light" implicit assumption in the 4th edition D&D setting? Heard it before. Those are all ideas from the first part of Iron Heroes setting chapter (more setting toolkit with example) rewritten to feature D&D trappings.
It's not a bad idea. In Iron Heroes, it's part of a package of features that establish the PCs as a few of the most important people around. Iron Heroes presents a world with little or no real order to it, and assumes that the players are among the few interested in and able to impose it.
It's not a bad way to handle big difference between D&D and the real world: adventurers. Yes, there's magic, but most settings tend to treat it like technology, and have it mostly controlled by guilds and the upper class. The presence of well-armed, socially mobile, mostly autonomous groups is a much bigger anomaly, because there's no real model for it.
Why are all these people mucking about? Why are they tolerated? Why do they want to go into this line of work in the first place? Monsters. Big, nasty monsters, roaming around the countryside. The world is a dangerous place, kings don't have a whole lot of direct control over the countryside, it's too dangerous for militias to handle on their own. Enter a small group of people who, for various reasons, are able to amass a great deal of personal power, and are all batshit insane. They go out, do a job that no one else can or will do but that everyone really wants done. And they don't even ask to be paid for it, because the monsters are all guarding treasure.
I will point out, though, that this situation works a lot better in Iron Heroes than it necessarily does in D&D, because Iron Heroes doesn't have reliable magic. D&D--as of Third Edition--tends to assume that there are a decent number of wizards and clerics hanging out in cities and towns, not necessarily associated with any particular adventure party. Wizards who can cast spells like teleport, and scrying, and sending, and clerics who can cast spells like commune. Finding out what's going on in the world is pretty easy for folks like that.
Though all that is, of course, subject to change. And they may choose to downplay the presence of powerful NPCs in 4th Edition--they did with Eberron. Almost all the really powerful characters are bad guys. Or they may make magic by default more unusual, like they've indicated they're doing with magic items.