First of all, Australia did not institute anything like an equal parenting time legal presumption, their reforms basically said that courts should consider it, but it was not anything like an equal parenting time presumption.
In Arizona, we passed a law that directed the courts to maximize the parenting time between the mother and the father. Four years later, we did a statewide evaluation that showed that the courts were implementing that as a legal presumption for equal parenting time, and that the entire family law community statewide evaluated the law positively. After four years of experience with it, we asked about whether people thought it was in children's best interests, whether it affected allegations of domestic violence, or whether it affected frequency of parent conflict and legal conflict. Overall, the findings were positive.
As Ms. MacDonald just mentioned, Kentucky just this past spring passed a very explicit equal parenting time law and the public opinion polls about it are strongly supportive.
Finally to your last point, I know of no state or country that has passed an equal parenting time presumption that then rescinded it. In fact, in Arizona our law was passed unanimously at the state legislature and enjoys the full support of almost the entire family law community.