Because 1 political party took all power and was able to use it against other parties. Eliminating parties creates dictatorship, you need 2 or more groups to keep the political discussion alive and dynamic.
There wasn't that much political will to change everything to a dictatorship when you wanted so. I will oppose and I'm sure that's an healthy debate: Patriotic Tyranny vs Participative Democracy.
About IMAGINE, it failed, it had a context, a purpose. There's people here that made it fail, therefore I question their purpose. You don't need to revive IMAGINE to recreate or rebuild it's ideals. Fresh ideas are very welcome.