First, from a professor: we do lots of alt-ac programming, but no one comes.
Second, from a student: I feel like if I prepare for alt-ac I'll damage my chances on the job market.
I started doing 'alt ac' work very early in my grad career. It made my work 1000x better. I don't regret it. But I suspect it made me illegible to academic departments.
I had co-authored publications, written grants, worked with librarians and archivists, and built digital projects. Departments didn't see me as one of their own.
First, most students are working two jobs: getting an education, and getting that education funded. Unless you are at the most elite institutions, time spent earning a stipend is time lost to research.
To make professional training work, we have to rethink scholarship.
Once you do that, though, higher ed is going to be so much better for it.