Considering that it's quite inefficient and written in Java, it might very well be. Especially graphics wise, it's nothing that mid to late nineties GPUs couldn't handle.
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.