1. Of course women can have it all. I am sorta convinced that to be successful in the art world one has to be slightly delusional. One has to ignore obstacles and just keep making your work from the "love of making." Being an artist is very hard and very rewarding, as is having a family, but neither excludes the other.
2. The art world is difficult whether you have children or not. I've seen some women become better artists when they had children. Now they had to succeed! There is no doubt in my mind that comparing a female artist in mid-career to a male artist on an equal level, career-wise, women get paid less, and being broke makes it harder to have kids.
3. There are many variables. It is just not an equal playing field in the first place. The obvious answer is that access to affordable, safe, and professional childcare for everybody would certainly help.