You can never have enough cpu power in gaming. You can always use more. The faster computers get, the more interesting games can get.
I've found the opposite. The faster computers get, the more games are all about BS graphics and nice explosions. Back in my day we had real interesting adventure games, now get off my lawn.
You can definitely find examples of earlier voxel renderers that are also more efficient than Minecraft(e.g. Ken Silverman's VOXLAP), but memory limits and networking gaps would remain real and intractable, limiting its potential popularity.
Those don't have much to do with Moore's law though.