Having worked for a bookbinder for about a year though I absolutely can assure anyone "hobbyist" binding has little in common with what professionals do. There is more tooling, more (expensive) machinery, more steps and more process refactoring. As can be expected, if someone's hobby is another one's craft and income. It's less of "The journey is the reward".

I’m having a hard time visualizing this. How do you use bookbinding techniques to make these things? I think I have a wrong picture in my head.

How did i build docking stations? Well, the way you create the back of a book (not of course the "inlay" or "pages") is usually by working on a thick board (you may call it "paperboard") and covering it with some sort of leather (my literal translation would be "leather paper"). With the same technique you can create other objects as well. Boxes would be the most obvious ones but any form that comes to your mind and you consider doable. I basically did that "around" a cable ;-)

He likes the work. He likes what he makes. He likes the customers. Seems like a good life, a good career path -- the kind of path programmers don't necessarily get to traverse.

Pictures of his shop: https://www.yelp.com/biz_photos/henry-bookbinding-new-york

http://www.yellowpages.com/detroit-mi/book-binding

Some on-demand printing services offer hard-cover bookbinding.

[1] http://www.ivrybookbinding.com/

That's not bookbinding, it's a cheap not-quite-replacement for the real thing. When difficult-to-replace volumes from your personal library start losing pages you see a bookbinder, not your corner photocopying business. University libraries used to have them on the staff, but they seem to have gone the way of the glassblower in the chemistry department. I understand that one can find still find bookbinding shops in strict-orthodox communities, people like to keep their prayer book, even after the original binding has given up.