Well, there have been many dead-ends in political evolution, but at the end of the day and all things considered and between one thing and another, one can say that:
Are actually healthy structural improvements in a society, and make it more fit to achieve any goal it sets its collective mind to. At least in terms of productivity, both economical and intellectual. It's also better at averting the Original Position Fallacy: the less the original position matters over your skills to keep it, the better the distribution of powers in terms of competence and work capacity (not accounting for the frightful overhead wasted in power-jockeying, but that can be moderated in a society where people are properly equipped to assess their own competence and that of others, so that they don't aim for a position they weren't capable of keeping).
See, that's the kind of thing I'm talking about. Except for the scientific method, I could take pretty much any of these examples and show that -- even assuming complete agreement on values, which by itself means almost begging the question -- the contemporary narrative of progress rests on the twin pillars of ignorance (or falsification) of actual history and arbitrary assignment of weight to trends that have gone in opposite directions. (And even for the scientific method, it can be argued that the contemporary official academic science is in far worse ...
I have found this most wonderful (if fairly lengthy) article, and thought you would enjoy having it brought to your attention.
It is so good, I think we should include it among the references in the "Politics is the Mind Killer" wiki page. But, before that, I submit it to you, and ask you: is there anything in this article that would warrant its exclusion from this site? I mean, besides the fact that it is about politics, and written by a notorious Social-democrat (And is that in itself grounds for exclusion?).