Once upon a time, writers were for reading. They were not expected to be performing seals. Instead, they did a series of carefully-placed media interviews and the rest of the book tour was in signings.
Gradually, the cult of the author has been growing and authors are marketed along with their books.
Authors have to be vivacious and entertaining. A good Writers' Festival appearance can boost sales. A tepid appearance may leave their books on the table.
Then there are the publishers' marketing people and minders who have to schmooze the festivals.
Who pays for what?
If the festivals pay to bring the writers, then they need the revenue from ticket sales.
One would have to ask the publishers how they make it viable to have travelling reps on the ground at events in these testing times.
We should not quibble, though. One thing is good and clear. Book festivals are big business in themselves. They are a sign of a curious and sentient literary market. Maybe a boom of Boomers.
I'm not complaining.