At some point we may end up with a brain(s) used to control the metaverse? Tad Williams Otherland series felt ridiculous toward the end, now I'm not so sure.
I honestly still think this is the real plot of the Matrix. They weren't batteries - they were cheap computing resources working in concert to literally create the Matrix.
Apparently that's what they intended originally. They wanted Morpheus to show a CPU instead of a battery to Neo in that scene. But they decided to not do that, because they thought that the audience would not understand what that is.
I don't know about controlling the metaverse, but my personal theory is that AI will be dominated by computer-integrated primate brains, possibly genetically modified.
