We operate our body with a single processor, the brain. Our organs are also managed by the brain. The brain is highly optimized to operate each of our organs, control motor functions, and allow us to think.
1 brain cannot control 2 bodies, there’s simply too much going on. Likewise, 2 full brains cannot control the same body, they would fight for resources. Organs keep the brain alive, the brain keeps organs alive. It’s a 1:1 ratio, sometimes less than 1, but never double (some have been born with extra controllable appendages but it’s few and far between).
Therefore, only a higher, more generalized, processor could handle operating 2 or more distinct beings.
If only our cells could talk.
Eh. Not really. I’d say it goes in the other direction, that the network can fragment into pieces which eventually coexist (or not), yet remain independent from each other.
As the saying goes, we are legion. Yet circumstances has us in a shared working space that requires a single, unitary voice. Interdependence dictated by environmental limitations. And should those limitations disappear, I’m not sure a person would remain a person for long.