A retiree who gets an average Social Security check of $1,400 every month and spends every penny of it is "contributing" $16,800 to the nation's GDP this year but is producing nothing. This number has to be stripped out of the equation when the U.S. government is borrowing $1.2 trillion every year to keep this person's check coming every month.
So now youre admitting that productivity has not declined, but youre moving the goalposts by wanting to take government spending out of GDP to make a point other then a measure of productivity.