I could not agree more with your ideas.
I think a lot of the problems with dance in the American academy, at least, dovetails with problems facing the humanities in general and physical education (when it does not concern big sports teams). In the early 20th century dance entered the academy either as a humanities discipline or as a part of physical education. And it was always the lowest on the totem pole.
Part of the problem also comes from within dance. For example, dance teachers, writers, and administrators continually say that dance is ephemeral when clearly it is no more ephemeral than any other performing art and it has a well-established notation system and just as much documentary resources as any field.
But, never fear: OSU now has a PhD in Dance; Temple University's Boyer School of Music has a PhD in Dance...and these programs are not Performance Studies.