I answered this several times in the thread: almost every book is out of print, including some of my favorites. I would be much more stupid and boring if I only read new books. And of course indicates why scribbling in a book is so terrible: if it's Tolkein or Susan Rice or Chem 101 7th edition then sure, whatever. But a lot of the worst scribbling comes from graduate students who don't value the text they're bloodlessly working through.

Some books and some editions in particular can be hard to find new.