alt Hacker NewsI think because the Minecraft world is like a giant tub of Lego. You go out into the procedural world to collect your pieces and then you create from that. It's actually your creations that are interesting and without them Minecraft would equally purposeless and bland.
That's exactly what No Man's Sky is though. There are entire communities centered around colonizing entire regions of the procedurally generated space. People build some seriously intricate bases and it really makes the worlds feel lived in.