Perhaps something which may be useful here is to look at a couple dictatorships that have been stable, and why:
North Korea survives on propaganda, isolation, and by keeping the population so poor and scattered that revolution is nearly impossible. The controllers have access to substantial power compared to the population as a whole, and the population is prevented from using their political superpower because they're too scattered and diffuse.
Saudi Arabia survives by having so much power and money funneled to the ruling class that the ruling class is able to keep the population in check. The population's superpower is available, but the ruling class has sufficient resources and control to keep the population from wanting to use it.
The common theme in both of these cases is merely that the ruling class is able to maintain a sufficient power gap over the population, which is effectively the same thing that happened in 1984. Some technologies make this easier and some make it harder. Nothing guarantees democratic organization, and advancement of technology may in fact lead to conditions that strongly prefer dictatorships in the future.
If nothing else, look at the "infinite paperclip maximizer" crowd and Eliezer's fears that a single AI would take over the entire universe: that's one of the most strict, unforgiving and inescapable dictatorships you could possibly ask for. It's such an inescapable dictatorship that Eliezer has set up an entire research institution dedicated to securing us favorable rules should one be set up.
Ultimately I think it's more interesting to discuss the conditions and requirements for stable dictatorship than whether or not dictatorships are more stable than democracies.
IIRC Saudi Arabians don't necessarily desire an end to the dictatorship? My impression was that due to oil, everybody has fair material wealth?
Orwell's Nineteen Eighty-Four is brilliant, terrifying and useful. It's been at its best fighting against governmental intrusions, and is often quoted by journalists and even judges. It's cultural impact has been immense. And, hey, it's well written.
But that doesn't mean it's accurate as a source of predictions or counterfactuals. Orwell's belief that "British democracy as it existed before 1939 would not survive the war" was wrong. Nineteen Eighty-Four did not predict the future course of communism. There is no evidence that anything like the world he envisaged could (or will) happen. Which isn't the same as saying that it couldn't, but we do require some evidence before accepting Orwell's world as realistic.
Yet from this book, a lot of implicit assumptions have seeped into our consciousness. The most important one (shared with many other dystopian novels) is that dictatorships are stable forms of government. Note the "forever" in the quote above - the society Orwell warned about would never change, never improve, never transform. In several conversations (about future governments, for instance), I've heard - and made - the argument that a dictatorship was inevitable, because it's an absorbing state. Democracies can come become dictatorships, but dictatorships (barring revolutions) will endure for good. And so the idea is that if revolutions become impossible (because of ubiquitous surveillance, for instance), then we're stuck with Big Brother for life, and for our children's children'c children's lives.
But thinking about this in the context of history, this doesn't seem credible. The most stable forms of government are democracies and monarchies; nothing else endures that long. And laying revolutions aside, there have been plenty of examples of even quite nasty governments improving themselves. Robespierre was deposed from within his own government - and so the Terror, for all its bloodshed, didn't even last a full year. The worse excesses of Stalinism ended with Stalin. Gorbachev voluntarily opened up his regime (to a certain extent). Mao would excoriate the China of today. Britain's leaders in the 19th and 20th century gradually opened up the franchise, without ever coming close to being deposed by force of arms. The dictatorships of Latin America have mostly fallen to democracies (though revolutions played a larger role there). Looking over the course of recent history, I see very little evidence the dictatorships have much lasting power at all - or that they are incapable of drastic internal change and even improvements.
Now, caveats abound. The future won't be like the past - maybe an Orwellian dictatorship will become possible with advanced surveillance technologies. Maybe a world government won't see any neighbouring government doing a better job, and feel compelled to match it by improving lot of its citizens. Maybe the threat of revolution remains necessary, even if revolts don't actually happen.
Still, we should refrain from assuming that dictatorships, whether party or individual, are somehow the default state, and conduct a much more evidence-based analysis of the matter.