As I said: there's about 5 to 8 books out there. How old is Writing Apache Modules with Perl and C? Please! Yes, there's a ton of good Perl books, but you will not find most of them at the big mega chains (ie, Borders, Books-a-million, Barnes & Noble). What you will find is the Camel, the Llama, the Rat, maybe the Panther, and a few others like Beginning Perl for Bioinformatics. But my point is that you will not find a selection that even approaches the Java selection. And quite frankly, I just find the Java titles a lot more appealing than titles like "Perl for Website Management" (which I'm sure is a great book, by the way) or "Perl for System Administration" (again, how long has this book been out?).
Just try to imagine yourself as a non-programmer or even a novice walking into one of these stores. Which language do you think you will be drawn to?