Minecraft is pretty much a technical phenomenon. It's a decade old, it's not fancy, but even now people are still playing it and modding it and taking the game to wherever their imagination will go. It's become part of many people's childhoods and even my closest friends, approaching their 30s, are still heavily invested in building their world in there, using various mods to basically recreate Civ and build out each stage of evolution.

You couldn't create such an inspirational game, or even an accidental ecosystem, by actually planning for it.