Bookseller Info Dump Time:
Like OP said, Signing hundreds of thousands of books is hard work. (Yes, some publishers domake signature stamps of super famous authors, but not as many as you think) Author signings are largely done by hand. It takes so much time and energy, nearly every author I've talked to about it usually dislikes the process, but they to do it, because they care for their fans. They'll carve out entire days to just sit in a publisher's office and sign books. It's a tedious task.
But people who love a signed edition usually don't think about the above. They usually don't consider what went into them receiving an author-signed copy of a book. Yet, I assure you -- in order for you to get that signed edition an author propbably lamented for hours, signing their name over and over and over.
Which is why some authors just don't do signed copies. Some authors only do in-person book signings (which personally, I enjoy best because I can chat to the author personally and the signature means more to me).
The question is, how can this signing process be made easier?
Well, glad you asked! It turns out in 2006, Margaret Atwood (yes, that Margaret Atwood) actually developed a tool to not only help with signing tons of copies, but it also allows authors to sign books - in ink - remotely! It's called LongPen.
Basically, it's an accessibility device. An author can do a digital book event, nowadays you can do live Q&A while streaming an author in to an event from anywhere in the world. And with LongPen, authors can also sign books without being in the room.
It's honestly revolutionary and an incredible accessiblity tool, because it allows more fans/readers to have the opprutunity to get their books signed 'in-person' without the hassle of authors travelling all over the world for book tours.
And I just think it's neat!