You should be gripping your bike mostly with your knees. Also, I think that sense of mechanical coordination is something most motorcyclists actually enjoy.
To refute your assertion more precisely, there is ample evidence that bikes have hand and foot controls that are frequently modified from the current controls. Some electric bikes move both brakes to the handlebars. Many roadracing motorcycles have added thumb brakes. And I've had plenty of situations on dirtbikes where I can't use to the shifter or rear brake because of silliness like water or mud. And then there's broken levers.
