Success or mistakes? Hard to say... I look around me and observe what we have done in the course of just the past century and it always comes back to it feeling like there's an eternal struggle between selfishness and greed... and idealism and altruism.
I don't know where it will all end. I have noticed a number of recent sci-fi series and movies where the current International Space Station still existed as the "core" of a much larger structure... and maybe that's what we're best at, as a species, "building on top of what already exists."
I really like that. We're adaptive by nature - and that typically requires a MacGyver-ing of existing resources in order to survive.
I'm strangely nostalgic (with respect to something I'll never visit) but I do hope we use the ISS as a core for a larger move into Space.