Joan Didion: Money was the Clincher?

It's rare for a serious author to be completely forthright in stating that money is their overriding creative incentive.  But that's just what Joan Didion apparently acknowledged in this interview about her new book Blue Nights:

Didion decided to return her advance to Alfred A. Knopf and abandon the book, which is titled after the long blue twilights of spring. “I thought, ‘I can just give the money back,’” she explains. Her agent and friend Lynn Nesbit suggested that she finish the book first and then talk about whether to publish it. Other friends urged her on. Didion tells me she finally looked at her book contract and saw how much she would have to return. “I could have bought an apartment with it,” she says. So she went back to writing the book.

Here's an interview from 2000: