I think it may be a bit of both the fact that he is older and that the book is pirated a lot. Concerns in the permaculture community have been voiced about
third ethic's impact on publishing, but from what I can tell with how many books and videos are still coming out from permaculture people, its effect may be minimal. Also, it may just be that he doesn't want the book to be an eBook. Not all elderly people are anti-technology, just like not all young people are tech-savvy.