I'd wager there's a relatively large degree of planning and coordination involved. Long term history has indeed seen a narrowing of that gap in -some- parts of the world, but recent history, especially in the united states, strongly indicates that gap is beginning to rapidly widen once more. America, in spite of being a highly developed nation, has a 'middle-class' under serious threat currently, and the planned 'austerity measures' coming down the pipeline seem to each have foreboding implications for people hovering above the poverty line. One disturbing but darkly amusing study I've come across suggested that if the money spent, in total, on the 2012 elections had been put toward the poverty crisis in America, there wouldn't be one. In any event, the lord/peasant dichotomy has only been applied regionally in the past. There isn't really much of a historical 'world' situation prior to modern times, as Globalization is a relatively modern effort. A 'unified' globe is a rather entirely new scenario, and that it's developing into the old feudal structures is hardly a positive thing.
It's easy to assume everyone's just blindly snatch-grabbing what they can, and the currently developing structure of the 'new world order' is just the chance result of those individual selfish efforts, and I agree that's entirely possible. Still, I think it's somewhat naive to assume that there aren't incredibly wealthy individuals, who've been incredibly wealthy for generations upon generations, playing 'the long game' out there. Just because the average person/government can't plan beyond the immediate future doesn't mean it's beyond everyone. If humanity ever wants to get off this pretty little rock we call home or transcend our predilection for war against ourselves (something I personally think is terribly unlikely to happen) a long-term plan, as in a plan that spans more than years or decades, but whole generations, is more or less essential. I think it quite probable that extremely wealthy, highly educated, and traditionally self-aggrandizing families/individuals may be attempting to execute long-term plans of their own, hoping to bring about a future that suits their view of how the world should be, or at least a future in which they remain firmly in the lead where the human 'race' is concerned.