How do you know that this earth doesn't need a North Korea so that people have an appropriate example of how not to do things? And perhaps the global economic crash is saving us from future, even worse, collapses by allowing us to put in regulation before true catastrophe happens.

Perhaps failure, as an aspect of learning, must occur in many ways and through many times to properly teach every generation how to act and how to better themselves and the planet. A 'successful Earth' where North Korea and economic collapses don't exist may just be a fantasized Utopia (as linked in your post), when what we need to access a better future is a Weirdtopia that includes them as counterexamples or pressure points for change.