This is kinda accurate but it's worth noting that even without highly developed technology, republics can still somewhat take place. Now direct democracies are impossible without the instantaneous speed of information, but, say, the early years of the United States weren't that much more technologically developed than the high to late middle ages. Now, granted, the United States of America, especially in it's early years, wasn't the most equal by modern standards, but it was still pretty equal compared to feudalism, and granted that the invention of the printing press was a pretty big deal, but a highly federalized republic is still very possible to have a republic type system with the technologies in the middle ages. Heck, take the Iroquois Confederacy, which despite having even less technology still were able to operate a republic-like system spanning a wide area. Or the Republic of Rome, which before it's fall held a great deal of land. We can all dispute the amount of equality of these republics, but it's still important to note that a great deal of people were able to influence the political process without the technology we have today.
During our current era of history, republics are seen as the norm and technology has reached new heights. While these certainly are correlated effects, it's important to not immediately jump to causation and assume that technology caused it, lest we in our folly allow the torch of democracy to be quelled.
Thanks for coming to my TED talk!