I like this quote because it's just so dreadfully realistic. It just discounts any belief in the power of heroism. Perhaps Winston is just a coward because the sight of the 110-pound brunette just scared the willies out of him to the point where he was unable to do anything. Perhaps he just lacks courage. Or maybe when it comes down to it, nobody really steps up and does the heroic thing when push comes to shove. That's certainly the general premise behind 1984. The Party will forever be in power because whenever a person could have the opportunity to stand up and be a hero, cowardice sets in, because going against the party is insanity and will be greeted with death. Really, all that's needed to end the cycle is for one person to stand up and be a leader within the proles. However, this will never ever ever happen. Orwell is essentially saying that nobody will put their neck out there because 1) Improvements are not guaranteed, 2) Death is a certainty, and 3) You will be deemed a lunatic by everyone else.
I, for one, think that what the people of 1984 really need is not a hero, but a legend.
Heroes get remembered, but legends never die.
Ten Bonus Points to whoever can list all of this man's titles in a comment below