The reality of software book publishing seems to be that you can make much more money writing a book, typesetting it into a PDF, and charging for downloads off your own website.
Ya, but someone from the class of writers like Charles Petzold isn't hurting one bit from one book not going big. He needs to write more mind-blowing stuff like CODE or maybe find another audience besides hard-core Windows programmers, which some might say is paradox these days.
With a service like Lulu, you can print any PDF-based (bound) book for about $20. Not that cheap, but getting better. I've published my own novel. There is no minimum - you can print one copy for that $20.
I have absolutely no problem with this at all.