Note that I agree with everything the GP poster said, but his comments do have an inkling of truth. We are experiencing an economic change in the United States, and may have been experiencing it for 20 years -- masked only by the 90s stock boom and real-estate bubbles. The change is characterized by lower-than-expected growth, and a difference in the way that growth has been distributed. Much of the growth is occurring overseas, and while Americans are profiting off of it, the profits aren't being equally distributed.
This may or may not have something to do with increasing world population, but in the longer term, we do face real population pressures. Not the Stand-on-Zanzibar strawman, where the country literally gets too crowded. Rather, we're facing huge resource pressures. There's reason to believe that our economy is already being constrained by energy resource limitations (read: oil), and not so much because the world population is increasing (though it is) but because large swaths of it have decided not to live in poverty anymore. There are 2.5 billion people expected to come out of poverty in the next few decades, and nobody has a clue how that's going to work. You could live in the middle of the Mojave desert and still be affected by that. And it's not just oil -- look up 'peak potassium' if you want another reason to be concerned. And of course, there's nuclear proliferation and climate change, which appears likely to happen whether or not you believe that humans are involved.
Many of these concerns can probably be addressed, but not by the economic system we're currently operating. So while I don't think that the Occupy protestors are explicitly looking three to four decades into the future, I hope that they're successful because the only way I see our way of life lasting 50 years is if we all make some dramatic changes to the way our government and economic elites behave. It's going to be a bumpy ride, and our current arrangement is like locking 90% of the population into steerage and driving the ship with abandon through a field of icebergs.