One friend in a group always leaves the burden of hosting to others.
I think we all have a friend or two who doesn't host/reciprocate. There are a number of reasons, some valid, but one solution is to start meeting in public places for coffee, happy hour, lunch or dinner. That way, everyone pays for herself, and nobody has to clean the house before and after, or wash dishes and glasses afterward.
Having a potluck is a great idea too -- but it still means that the homeowner has to clean and provide set-ups for the food, etc.
I was that person who never hosted after my divorce. Perhaps the friend was burned out on hosting, I know I did not want to do it anymore. Her friends should have a potluck at her place to help out and that would be a good rule going forward. Simply not inviting her with no explanation is not nice, so these women should talk to her about it.