Mmmmmmmmmmm It's a double edged sword. I always remember a bit of advice that after publishing and ring-binding the little telescope book. The first thing the buyer will do is to photo copy it and sell a few copies to his mates. Yes, it DOES happen - I've seen it with my book, with my own eyes. So why would anyone spend time and money printing these books when he KNOWS that they'll appear reprinted downloaded or just copied.
Some want the expensive originals, some want a cheaply priced good repro for their library some just want a free download or copy
I've said my piece. Maybe others could come in to agree or disagree. As a matter of interest, I have an interest in this because my son (then aged 16) was caught downloading music from the web and ignored the publishers call for £400 compensation. It didn't go away and a summons ensued. I had to pay £500.