I disagree... Price is dictated by supply and demand. Industries are paying nothing for these interns because they can get away with it, not because they consider them worthless.
You pay nothing to breathe oxygen. How valuable is it to you?
You pay nothing to breathe oxygen. How valuable is it to you?
When you do unpaid work, it means that it's work that doesn't matter, which means it isn't providing you with much in terms of valuable skills.