What is private decline depends partly on definition. For the most part declines occur in private enrollment shares, rarely in absolute numbers. Declines also sometimes occur in private subsectors rather than in the private sector overall. Some declines are merely transitory. Short of actual decline we also find notable slowing of private growth rates.
After citing notable historical examples of private decline, we focus on contemporary social factors and political factors. The social factors revolve around two main dynamics: diminution of social distinctiveness or groups that have fueled private growth; demographic changes that fall hard on private sectors. On the political side we consider political regime change and regulation, then shifting to analysis of hefty multi-dimensional expansion within the public sector.
None of these dynamics reverses the continued dominant tendency of private growth but they do provide counter-tendencies important to grasp and with potential to accelerate.