[adventured]

Maybe it separates the development teams in a way that they didn't have to rely on the whole potato being literally integrated. Microsoft, like many huge companies, is known to be hyper territorial. With the computational resources available, this might have been both a pragmatic and easy choice. Each group perhaps wouldn't have to be so careful about crashing the rest of the system, and it might make it easier to develop and update each segment individually.

This might also make it easier to rip pieces off later, or add large pieces later, without needing to do a comprehensive integration across the Xbox One system, while keeping everything in its own sandbox.