Because plenty of them aren't out of print. Publishers may or may not give a shit if you put forward a book in a fashion that does not impact them monetarily.

Because plenty of them aren't out of print. Publishers may or may not give a shit if you put forward a book in a fashion that does not impact them monetarily. They give a shit if you do. They definitely don't care what the ratio between the two is; they care that the latter is non-zero.