Making the expansion permanent will reduce the incentive to work and get married for parents, without having any positive impact on intergenerational mobility.
The incentive for parents to work and get married would be reduced if the expansion was made permanent, all without having any positive effects on familial economic mobility. The incentive for parents to work and get married would be reduced if the expansion was made permanent, all without improving familial monetary mobility.
Making the expansion permanent will reduce the incentive to work and get married for parents, without having any positive impact on intergenerational mobility.