Well, musically, at least.
In this modern age we live in, cloning is finally here. No, you can't create your own Mini-Me yet, but it's a lot easier to at least simulate being an identical twin/triplet/quadruplet and so on.
I was hanging out with friends on Saturday night, and my friend Collin asked me if I'd gotten his e-mail about the video with the guy singing all the parts to some Michael Jackson music himself. I told him that I hadn't received his e-mail yet, but that yes, I'd seen that video with the guy singing "Thriller." (I was thinking of the following video.)
However, I later discovered that my friend was referring to another video involving Michael Jackson music and cloning.
This reminded me of this John Williams/Star Wars tribute I'd seen a few months prior:
As equipment gets cheaper and distribution becomes easier, the one-person recording phenomenon has become increasingly huge, and the idea of having an actual group/band increasingly unnecessary. That's not to say that there's not still magic in collaboration that can't necessarily be duplicated on your own, but the loner now has options.
So, the clones are taking over. Don't try to fight it. They are unstoppable.
Finally, to end on a tangent, the video that my free-associating mind also thought of based on this discussion, and perhaps my favorite of the bunch: