Most of those countries have not been democracies for very long. The United States used to have many of those checks and balances, all of which were systematically ripped out by the relentless political machine. Give it another century, and even with proportional voting or citizen's veto's, things will still probably end up in a similar state.
There are also countries that are real democratic countries that are older than usa. They have not been corrupted like usa, because they have proper discourse and discussions by its citizens, which doesn't happen in usa. Even usa can be reformed to be a proper democratic country within 1 or 2 years or even as short as 6 months, if proper consensus can be formed by people. Institutions doesn't matter as much as people and real democracy isn't hard to implement if there is political will for it. Current usa is an anti-example of what a democracy should not be.
Democracy itself is young concept. So there is no point looking beyond a certain time period as they were all monarchies before that. However even during earlier times there are examples of democracy like monarchies where citizens were not ignored by monarch, and they ruled for the people.