Same for Quake. BSP tech came from the field of medicine, for example, and rasterization wasn't new. Quake just did it so much better than anyone else, along with a fun game. As with Minecraft.
BSPs weren't new to the Quake engine (Doom had them). Gouraud shading, lighting, and TCP/IP multiplayer are what made Quake revolutionary for the PC. These things existed on SGIs costing $100k for years before too. The optimizations to make this on a PC is why Carmack is genius.
Not to be pedantic but TCP or UDP? I always thought games preferred UDP as it's much more efficient if you don't care about a fraction of the packages being dropped?
There's relatively little that's truly new in Minecraft. Both the voxel aesthetic and many aspects of the world and gameplay come from its beginnings as an Infiniminer clone. Notch 'just' made the right adjustments to the formula and then nailed the execution.
