I don't think that it is so much short memory, as it is a crippling addiction to comfort. People in America basically know that the president is a liar and the whole government is full of back-scratching money-launderers. Why else would half the population refuse to vote?? But what would revolution entail? A grinding halt to consumerism? The over-filled nut-houses and jails to unleash hordes of killers onto the streets? A global halt to commerce and technology? I guarantee you Bush or Blair or any other friendly despot will not step down without insurrection, and the people are just too cozy and wrapped up in their own lives, with TVs, computers, paperback novels and what have you to stand up and fight.
Its a simple, Roman formula; bread and circus. Give people a moderate, dependable lifestyle and they will serve you with the utmost devotion. Especially the US, which is still primarily a nation of people who oft came here from the oppressed, underclasses of Europe and worked their way into a stable middle-class lifestyle after a few generations.
Is it a conspiracy involving reptilian space aliens?? Probably not. I find Icke entertaining, but it seems like he took one to many psychotropic compounds in his hippy days. The extent of his reptile theory would basically mean that all of humanity is participating in a giant scheme to trick ourselves into a convoluted conspiracy, against ourselves.
My theory is pretty simple, that humans will do anything for power. Look on a microcosmic level, a guy beating up another guy and stealing his bike. Is there a grand conspiracy? No, it is just a display of primal aggression which is motivated by selfishness. Same with the government, a primal display of aggression on a large scale, ensured by worldwide intergovernmental rings of bureaucracy, militarism and policing, all in the interest of preservation of commerce, which ensures a passive population.