Intern-al affairs

When I was a kid, the only intern I knew of was TV's Dr. Kildare. Now as I comb the job vacancy lists, the most frequent word I read is "intern".
Now, correct me if I'm wrong, but isn't an internship meant to be a professional training of some kind, on the understanding that if you make the grade, there could be a job at the end of it. And traditionally, internships cover your expenses or pay a small stipend.
These days it seems there is very little likelihood of getting a paid position at the end of internships which typically run from a month to six months. Heck no. They just replace you with another eager and willing pair of hands, desperate to get a foothold in their desired field.
What's more, most interns complain that they get no travel or food expenses. This means interns are actually paying to work, which just doesn't seem fair to me.
Why not just come right out and say it: "Come and work for us for free, then get back in the job line. Sure, you'll have some valuable experience that may include being a general dogsbody, but whoever promised you more than that? Next sucker, please!"