Ok here's my take on your situation. First of all I don't see why getting a salaried job would be so bad for you. You're an MIT Grad, that alone will get you a high paying job anywhere in the field. Second you know your stuff and you seem like a pretty smart guy.
Sorry about your royalties being cut short and I really do understand the "I have to provide for my family" situation. But here's where I stand, I'm actually glad people pirate ebooks. Let me tell you why. Consider my situation, I'm a CS Student with a part time job and my source of income sure enough is not even half of what you make in royalties. I simply don't have the money to pay for most of the books that are required for my classes. So anytime I find a pirated book on the internet that otherwise would cost $60/$100 I jump up with joy. After all I'm saving my cash. This last statement sounds a little selfish to most, but I believe is not. You have a degree David (From MIT) I've might add and I don't. If resources are available online, that are going to make me a better programmer and give me a chance to better my future from learning these skills I'm sure as heck going to download the book. Plain and Simple. I believe information should be free for those that are striving to achieve something. Lastly If anything that I said offends or ticks you off, I would simply advise you to look at things like this. Maybe your royalties are decreasing but your book is helping this individual secure a better a life for himself. So I would like to Thank you none the less for a wonderfully written book.