That schedule might work for "parenting" but would be horrible for the relationship of the couple. People often try to view parenting solutions in isolation and forget that this is the lives of 3+ people we're discussing. It's the same as work to pay for daycare. If a stay at home parent works 2-3 days per week, and their income only covers the expenses of going to work, they still get benefits. They stay in the job market without a multi-year break, in my country they accrue superannuation payments, and it gets them out of the house with a break from the kids (parenting constantly is hard mentally).