We're already merged in the sense that we delegate a lot of our thinking to machines. We don't memorise details any more as we know they are at our fingertips. Instead we optimise our thinking and memory around the services provided by technology.

IMO, the physical integration will advance in line with the removal of the mouse as a peripheral - combination of brainwave interface and ai motion tracking will change how we interact with computers and this will open the door direct synaptic stimulation, essentially putting google into our cognitive reach without a screen. From here conscious and even subconscious processes may be delegated to the cloud.