As I read it, things usually get better during long periods of difficult reform, but worse after a revolution. Sometimes when the balance between big powers changes there are opportunities for small nations to reassert their independence from an external tyrant, but that isn't a revolution in the same sense.
The 1917 Russian revolution would be an example of things getting worse after a revolution. The French revolution results were more mixed, but some things got a lot worse for a while, and its debatable how much the revolution itself really helped. The 1989 Polish revolution would be an example of escaping from an external oppressor, where things got better because the society was already capable of supporting a much better order than had been imposed from without.
The problem with revolutions, is that the a corrupt society is usually corrupt at more than just the top level - the people who abuse power at the top are able to do that in large part because of the corruption of those below them. When they are overthrown violently, even worse elements are commonly able to take advantage of the breakdown in civil institutions.
I'm not defending the people at the top - I hate the 1%. And I'm not against violence where it makes sense. But if people had what it takes to make things better after overthrowing their moneyed overlords violently, in most places they have what it takes to do it better without the violence. We have a lot of power already. If we don't use it because we're lazy or busy or brainwashed, a revolution isn't going to help with that.