Why is there no eBook of Future Shock?

Yes, but not prohibitively so, certainly not for the largest trade book publisher in the world. Ebook conversions is part of my job, and for a backlist title like this, where you're working from scanned pages, it's a bit of a pain. But more likely it's a rights situation. The publisher would have to go back to the estate and renegotiate that, and that would almost certainly be more costly than your production expenses.