The only way it gets printed is if Heroku decides it feels like allocating time and resources getting this printed by working with a publisher, which is way outside our usual line of work there.
I don't see the incentive for the corporation to do this, financially or otherwise.
I've just bought a hard copy of LYSE to say thanks. I own almost no physical books these days, but you are worth it. Thank you!
The issues I can see with putting the source itself open is receiving pull reqs, which quickly turn into an issue of copyrights and form-waiving and all kind of stuff I'm not comfortable running around with.
I have a friend who's currently playing with making the conversion work with far more determination than I have, though.