Matthew - I'm in your camp here, I think, unless I've misinterpreted your response... The economics of labor in this business are TOUGH. And change, all too often, happens slowly, from the bottom up.
That said, I'm astonished: seven internships is a lot of work. While I'm happy to have done intern/apprentice jobs before, during and briefly after college, I question the habits of people who are truly serial interns. Even if we set aside the issue of working well below a living wage, these are still entry-level positions. Most arts internships, as advertised, run between two and ten months. Taking the average of that, should we expect that any early-career worker needs to spend between five and six years honing their craft for minimal pay? This is further complicated by the reality that a college degree is no longer special qualification, and recent grads often seek internships as a way to transition into the professional world. Four years (or so) of schooling at the college level, followed by five or six years of entry level work, sounds extraordinarily inefficient to me.
Perhaps I'm drawing a line in the sand... but it seems foolhardy, after the third or fourth such experience, to imagine that an internship will lead to employment. Applications for other jobs - with the same organization(s) an individual has interned, with different ones, with any companies at all - lead to paying work, higher on the totem pole.