This provides a potential alternate explanation for the decline in reported applications. Fewer Ph.D. programs reporting data would naturally lead to a lower number of applications reported.

The potential impact of an increase in average age of applicants is unclear. If anything, this might suggest fewer “recent” (and therefore, on average younger) graduates are applying, which is consistent with the author’s reasoning.

This raises the possibility that the data the author relies on has become less reliable. The decline in reported applications may not reflect an actual decline in applications.

This raises a potential alternate explanation for the decline in reported applications. Maybe interest in pursuing art history as a career is just as high, but more graduates are being hired directly by employers in the industry rather than pursuing a Ph.D.

This raises a potential alternate explanation for the decline in reported applications. The decline might not be coming from North American graduates, but from people outside North America. Thus, it doesn’t necessarily reflect decline in the interest of North American graduates.