Her publisher in the UK, Granta, signed up to the programme, but only for those two books and for (AFAIK) no others so far. She pretty much had to bully them into doing it. Once you've signed the book, the e-book is free (bar a small processing fee). the process has worked nicely and though the publisher hasn't pushed it hard, and we haven't yet seen huge uptake, the future looks bright.
We tried to get the US publisher (Norton) interested and they could not be persuaded. Perhaps now with all this publicity they might be.
When it comes to new tech and business methods, the publishing industry might be even more of a sclerotic dinosaur than the movie industry. Don't get me started on the horror that was getting an enhanced e-book (with slides, audio, video etc etc) done.