Might have something to do with the fact that they didn't try with female characters after Supergirl and Catwoman.
There was, if memory serves, a 20 year gap between SG and CW, and a 15 year gap between Catwoman and Wonder Woman and there isn't a single critic who I ever read who blamed Catwoman's crash and burn on having a female lead. It was a terribly written movie that didn't resemble the character from the previous Batman movies. Supergirl had some seriously hideous dialogue and a lame plot that fell flat. Both movies were complete garbage from start to finish, but so are a lot of male led superhero movies, yet that doesn't stop them from trying again.
Wonder Woman and Captain Marvel will hopefully turn this around, but I wouldn't put it past movie execs to stop making female led superhero films the minute one tanks.