One of the keys to totalitarianism is technology. If you look at older societies, even as recently as 500 years ago, there were limits to what central governments could impose on people. Queen Elizabeth wasn't sure she could control the nobility, so she went on 'progresses' from region to region to keep an eye on every local leader. There really wasn't much question of her exercising direct control over those nobles' subjects.
Nor could rulers insist on great ideological uniformity. The story of Christianity until a few centuries ago was orthodoxy combating heterodoxy, inquisition, purges, etc. The Holy Roman Empire recognized that it could not impose conformity on the German states, so it let princes decide on their followers' religions. Going further back, ancient Israel was even more diverse. The YHWH cult never displaced the popular religions; and the state religions of Egypt and Mesopotamia were largely limited the ruling elites.
Modern communications made totalitarianism possible in the 20th century. Hitler, Stalin, Mao and the others used communications and internal espionage to create a pervasive state-cum-cult that was previously impossible. North Korea may be backward in many ways, but the central government has modern technology and organizational resources that enable it to command popular obedience--to some degree even loyalty--of a sort most tyrants could only dream of.
Ironically, we've seen the importance of communications and technology even in the "free" world in recent years, with some governments using media manipulation to interfere in other countries' internal politics; and some governments using the media to alter their own public's perceptions of reality. George Orwell was right when he wrote of a new totalitarianism based as much on communications technology as actual power.
A large and populous empire like ancient Egypt could not possibly be as effective at control and suppression as today's North Korea.