Research overwhelmingly shows "alternative" family types to be markedly inferior to the two-parent intact family when it comes to the safety, welfare, development and happiness of children. Family disruption puts more children on a downward course, creating patterns of disadvantage which are intergenerational. Risks of any adverse outcome are usually at least double for youngsters from disrupted and lone-parent households compared with intact families.
Family disruption is driving the recent marked rise in youth homelessness, which has fundamentally altered the nature of the homeless population. Far from creating that "powerful and supportive structure", the re-partnering of parents means abuse from stepfathers, or abandonment, abuse and neglect from mothers with boyfriends, which pushes children out of the home. Children of disrupted families have weaker relationships with both parents in childhood and adulthood and receive less help, just as parents who experience marital breakdown are less likely to get support from relatives and less likely to have obligations to in-laws.
There is more in folklore than maypoles. There are many variants of the story of Cinderella: perhaps Christine Hardyment should listen to what they are trying to tell us about the supportiveness of the "maypole family".