That was my thinking too. Not everyone has been or will be interested in (slow) movies, but historically those people wouldn't be studying film. It's not exactly a lucrative field.
I wonder if the students are going into film but actually just want to work in social media in which case it all makes sense.
"Overall [social media] platform use slipped ... especially the youngest ... who no longer use social media at all" is the kind of wild claim that requires a much more significant investigation than this author undertook.