A growing view of colleges and universities as hostile environments for those with conservative, libertarian, and dissenting views.
At the same time, many are simply rejecting higher education as an option due to a mix of high costs and lower relevancy for them personally. The view of campuses as places of indoctrination also likely plays a role in that trend. Few conservatives relish the idea of paying high tuition to have their children spend four years with unrelenting attacks on their views and values while limiting their own speech opportunities.
The same view is growing among donors. The ideological intolerance has led donors to pull their support from schools like, most recently, the University of Arizona.
This trend has worsened as our faculties have become less ideologically diverse, except to the extent that they reflect a diverse spectrum running from the left to the far left.