It doesn't tend to be local early ones that are the problem - the author can generally rent a crowd - but later ones. We had the bestselling author in the UK at one and had 3 people. We drafted staff in to zip up their coats and smile sweetly. As she was the bestseller or romances for the 50-year demograph and most of our staff were schoolleavers she probably copped us.
When a book comes out, it is always wise to invite family and friends to your first signing event (you can usually get them to come back for subsequent books if you bribe them with a party afterwards, but not for the same book) so that you have people to talk to and it at least has the
atmosphere of an important event. (And the bookstore doesn't care if all the copies they sell that day go to your relatives and friends. A sale is a sale.)
I've been told -- and you will know better than I, springs, to what extent this is true -- that for the author the value of a book signing (unless you are someone so important you can be sure of a crowd) is usually about signing books in stock (less likely to be returned if they are signed) and making friends with the staff, so they will recommend your book to customers. If you actually sell more than a handful of books, that's a bonus.
It makes me feel much better about some of my signings to know that even best selling authors have the same problems.
But Mark Robson, who used to be active here, was always able to rope in new readers, because he was outgoing and had a winning personality, so that he would address those who passed by his table and engage them in conversation. And when that didn't work, he'd go out into the aisles and offer to help people find whatever they had come into the bookstore looking for (having arrived early and memorized the layout of the store in advance) and start a conversation with them that way.
For most of us, however, a book signing can be an exercise in humiliation. Especially when the bookstore has done no promotion and they stick you at a table in a dark, dark corner. Which does happen. They'll stick you in places so hard to find, you need a ball of twine and an obliging maiden to help you find your way back out.
I have to agree with that article that being an author is not a job for those who start out with unrealistic expectations. That way lies bitterness. On the other hand, if you know what to expect, and you are writing because writing is what you really, really,
really want to do for its own sake, there are rewards.