Judy Blume on Income Disparity

Judy Blume has an interesting interview in the June newsletter from Goodreads, about the release of her newest adult book In The Unlikely Event and questions about her career. I was struck by this section about her early career:
"The women's movement was just coming; we were very slow getting it in New Jersey. One thing I remember is, I was very shy about asking for a larger advance. I only knew what I had read in a magazine called Writer's Digest, which said you should get $1,000 for your book, and I had gotten $800, and I said, "Isn't it supposed to be $1,000? And they said to me, Yes, but we want someplace to go with your next book. I do remember a time when I was more successful. I think my former husband put me up to it, asking for more money, and I was told, "You have a husband who earns a very good living, and so you don't need to do this. Money will come back to you in royalties if the book sells well, but you don't need to do this." And I believe I had an agent at the time." [emphasis added]
So basically she was told, "You have a sugar daddy supporting you, so we shouldn't have to pay you as much money as we pay men." Wow. That just croggles me. (Hard data about authors' advances are hard to come by, but I wonder if anything like this still goes on?)