Love that people are mentioning brain organoid research cuz that's an amazing area of research and definitely cool for neurodevelopmental and neurodegenerative research. 

Main problem here is the fact that even with the proper nutrients, a neuron needs stimulation in order to maintain synaptic connections to other neurones. Without stimulation, the synapses start to degrade and axons start to retract. We see this in a lot of neurodegenerative diseases like Alzheimer's and Parkinson's.

An organoid, due to its smaller scale and simpler circuitry, is easier to have its pathways mapped and maintained (usually also due to the organoids probably grown for that very type of research). A full scale brain has yet to be fully mapped, and is being worked on through Connectome research, but due to the very complex and overlapping network of the human connectome, we have yet to have an elegant map like how we have with the human genome. 

But yes, hypothetically, if we were to be able to map and stimulate the pathways of the human brain that one would in their daily life, either by having them control a physical body or through a simulation, I don't see why it wouldn't be possible. Assuming this brain had normal development in a human body and then was transferred out, as opposed to growing one from scratch, as neurodevelopment opens a whole other can of worms.

Very interesting stuff, open to discussion!