Inside scoop…the voice recognition tech is not working as it should. The speed at which the CPU, or even multiple CPUs, need to operate in order to recognize the aircraft involved and the control instructions, then order the CG aircraft to perform the action, is just too fast. This really comes into play when the simulation is generating and moving multiple CG images and targets simultaneously, often ten, or twenty, or more.
And just to be clear, the FAA does not hire controllers, except out of the military or from previous experience. The majority of hires are candidates, who only become controllers through completion of their training program.