I'd like to offer a more optimistic view.
The true advantages of democracy are things that are rarely talked about and which people are mostly unaware. In my opinion, they are:
1. The availability of non-violent ways to push for change and seek redress.
2. A way to reliably and peacefully transition from one leader to another.
These are big problems with non-democratic governments. If people don't feel like they have a chance to change the system from within, they'll eventually resort to violence. If there isn't a widely agreed upon way to choose the next leader and transition power to them, then there will be succession struggles.
In a healthy democracy, people are encouraged to seek change politically, and the people accept the outcome whatever it may be.
As Scott Alexander put it in his Anti-Reactionary FAQ: "If you remember nothing else about the superiority of democracies to other forms of government, remember the fact that in three years, we will have a change of leadership and almost no one is stocking up on canned goods to prepare for the inevitable civil war."
Note that these advantages do not depend on making good choices. They only require the availability of choices, and widespread acceptance of the outcomes. Obviously, making good choices would be really nice, but they aren't the best feature of the system.
This is actually what troubles me most about Trump. Bad policies and terrible morals are one thing, but he directly attacked the very notion of democracy itself. All the talk of the election being rigged and perhaps not accepting the results is setting up his followers to reject the entire system, not just his opponents. And I find myself sincerely wondering if he'd willingly leave office in 2021 if he loses the next time around, or in 2025 if he wins.