Why, after more than two hundred years of the founding of the United States, has there not been a single dictator?

The separation of powers is indeed the founding system of the United States, but it is not the fundamental system of the United States; in the fundamental system of the United States, there are systems that are far more important than the separation of powers.
The so-called separation of powers is actually nonsense; the essence can be summed up in two words: separation of powers.
Why decentralization is important? Because the United States is a democratically elected country that does not allow the emergence of dictators. Dictators are enemies of democracy, and it is democracy that has unleashed America's productivity, allowing the U.S. to dominate the world. Dictatorship can only lead the U.S. into a bottomless abyss.
The only way to defeat a dictator is to decentralize power.
The progress of human development is due to the distribution of power from the emperor, which liberated thought and productivity.
The decentralization in the United States is comprehensive:
1. Horizontal decentralization. This is what we refer to as the separation of powers. In fact, many departments in the United States are mutually independent and do not interfere with each other, not just the three branches. All top-level agencies in the U.S. are semi-independent and are only accountable to voters. The correct understanding is N-way separation of powers.
2. Vertical decentralization, the president cannot direct governors, governors cannot direct county magistrates or mayors, and county magistrates and mayors cannot direct township or street offices. They are all elected by voters, with no hierarchical relationship, only accountable to the voters, which is far more important than the separation of powers.
The president has no power to appoint or dismiss them. The president seems to be in a high position, but in fact, they can choose to ignore him if they want, or they can choose not to.
In addition, if voters are dissatisfied with the president, they can use their votes to force him out of office. If he dares to go against the votes, there are guns to drive him out.
Of course, even the President of the United States finds it difficult to pass a single barrier of the separation of powers in Congress, let alone tackle other obstacles.
The United States decentralizes power significantly, delegating it all to the people, fundamentally not giving the U.S. president any opportunity to lead as the helmsman.
Americans are very confident, believing that justice is with the people. Americans do not need the sun, nor do they need any leaders to guide them; they are their own light.