I voted for the only option that allowed me to not say for certain what the answer is.
The field, the city, the amount of students saturating the potential interns, the perks of the internship, the actual work you will be doing, etc. all determine this. In other words, it's entirely situational. Maybe it's not that 98% of them are unpaid, maybe it's just that you haven't been looking in the right places or being assertive towards offering your less-experienced dirt cheap services to companies. I mean, the ones you hear the most about are probably going to be unpaid ones as it's cheaper to have one person in their company take 5 hours out of their week to whore themselves out to all of the colleges and recruiting sites to pick up some people that are desperate to get their credit hours. Why pay someone for the work if there are clearly people willing to do it for free?
My brother worked at a radio station for a while and was responsible for the interns. They were unpaid internships and they had to have about a dozen hours in the office a week and attend at least 2 events a week for around 20 hours. The benefit to them was that they got some great experience and exposure and built a hell of a network... on top of getting to see a free occasional concert, they got to meet plenty of celebrities, see lots of free movies, and have flexible scheduling. My brother did his best to help all of the ones who were great at the job to find a real job when they were done, even if it wasn't for his radio station. Worth it for these people? You bet your ass.