There may be many reasons but I believe the key reason is the lack of voter training in decision-making. Deciding who to vote for is far simpler than making executive decisions.
Most people are educated to obey, not to decide and live with the consequences.
When kids go to school, we teach them subjects. They are also taught to behave, to share, to respect others, to express themselves, etc., but we do not teach them to decide on issues that affect their daily lives as students.
Kids have no say on when to take a break, where to seat, what are the most comfortable chairs to buy, how long a class should last, what would be a fair punishment for misbehaving or the right reward for good behaviour or for good marks, or if there should be marks at all, what sports to play, etc.
As kids grow up, in high school and university, the same pattern continues. Students have no real say on how the school or university functions, other than through demands and protests. They do not decide on how the school or university runs; mostly their role is passive.
At work, in most business and public services, employees have to do as they are told. They do not decide on how to manage the organization.
As voters, we elect someone, but that’s it. We do not have the power to make executive decisions, to decide on laws, treaties, taxes, etc.
Direct democracy can only function if most voters feel comfortable deciding, but decision-making requires “training”.
There is more; being trained, mostly to obey, has other negative consequences. One of those is that it predisposes us to look for someone to tell us what to do; we look for “leadership”.
But that happens because we have not experienced that a decision, rationally, calmly discussed by the citizens, by the people, is superior to the decision made by one person or a small group provided, of course, that the most capable also participate in the discussion. Such collective decisions are also more readily accepted by those affected by it.
Let me say also that the Greeks invented direct democracy, not representative democracy. The difference is that in a representative democracy, the people elect those who decide, in direct democracy, the people decide.
The push for democracy started again in the XVII century. Unfortunately, almost 1700 years had passed since Greek direct democracy; society was not ready for direct democracy and settled for representative democracy. But the time has come to go all the way.
Representative democracy is not “rule by the people”; it is “rule by those elected” by the people. The executive power lies with the elected representatives, not with the people.
The ancient Greek democrats would consider current representative democracy as government by the oligarchic class. The class made up of politicians, political parties, lobbies, and opinion leaders. That our “oligarchs” are elected would not change the assessment ancient Greek democrats would make.
The growing dissatisfaction with representative democracy, in many established representative democracies, is the logical result of not being democracies.
There is only one modern country that has adopted direct democracy, although not completely; Switzerland.
Why Switzerland became a direct democracy at the national level has its origins in the ancestral “village and town square assemblies” of the 12th century, and also from Greek influence through the French and American Revolution. As we see now both, the French and the Americans have not gone beyond representative democracy, not yet.
In modern Switzerland, the popular referendum came about after the elected government in Zurich mismanaged an epidemic, the people of Zurich decided “we can manage this ourselves”. From Zurich, it spread to the rest of Switzerland
At first, the Swiss elected representatives did not like direct democracy and opposed it, but now they accept it. Even better, often it is the Swiss politicians who push for important decisions to be taken to the people.
As you might have guessed, the Swiss people do not look for “leaders with a vision” to guide them; they have learned to lead themselves.
If you like direct democracy for your country, start by pushing for it in schools, and at the local level. They will be good “training” to bring direct democracy at the regional and national levels; it will be the first step to fill the gap in our thinking about the ability of voters to make executive decisions.