I think it’s pretty forgivable that they wouldn’t have expected BoP to bomb. Harley Quinn was the most popular part of the financially successful Suicide Squad, and Margot Robbie seems to be a popular actress. Meanwhile, Wonder Woman was a critical and commercial success that had great legs for a superhero movie, so it’s not shocking that they’d trust Patty Jenkins with this one.
Ultimately though, I guess 2020 just wasn’t DC’s year, especially after 2019 turned out pretty good for them.