I got couple of good definitions of the traditional Print run. One of the disturbing things mentioned in one of the definitions that many a times 50 percent of them are destroyed. How it was destroyed is not known but if it has anything to do with burning of books or something, bad for everybody. I am surprised if that used to be the case.
I come from India and here for most people one big source of fiction books has been something called booksbyweight https://www.facebook.com/Booksbyweight/ . This is very popular with millennials who go to discover new authors, new genres at very low cost.
While this is good for the seller and probably a bit for Publishers, are authors compensated for it ? I would also ask what authors think of it.