At least one example is the orders-of-magnitude advantage that today's tyrant has in the amount of dynamic information he has about each and every serf with which to enable, strengthen, and perpetuate his control.
In their wildest dreams, Dzerhzinksy, Stalin, Wolf, Hitler, Goebbels, Malenkov, and Khrushchev couldn't have imagined the top-to-bottom control of every aspect of the serf population's life that is now a simple reality.
The history of the entire 20th century would have significantly different.
Reagan's 1964 warning of "...the last step into a thousand years of darkness." has certainly come to pass.
Yes, it’s true that modern technology is a force multiplier, so much so that it “generates its own weather”, so to speak. The monarchs, despots and tribal leaders of pre-World War 1 times were largely content to enlarge and otherwise rule over their own empires. Modernity has seen the rise of malignant megalomaniacs driven solely by the will to power; they use that power in pursuit of their savage, murderous Utopias. What they demand is not mere loyalty or economic surrender, but the very extinction of that which makes you human. This requires the elimination of even the smallest hint of dissent and thus - the slaughter of millions. It is the ultimate exercise of power, and it is absolutely irresistible for some. We see their handiwork everywhere today. The abyss beckons, and they are only too willing to plunge headlong into it.