Humans can only focus on one thing at a time. So why are we spending money to display multiple things simultaneously? Would the author use that logic to argue

Humans can only focus on one thing at a time. So why are we spending money to display multiple things simultaneously? Would the author use that logic to argue that no monitor should have more than a single pixel? While there might be a point where adding more monitors becomes pointless, it's not two monitors. Two monitors still cover a small area, compared to a human's full field of view.