Do we have a good economic narrative for unpaid internships outside of naturally abusive talent driven industries (music, film, journalism)? Do internships just fall in this hole where you'd like to have an office wench but can't quite justify it in a budget, or is it entirely a made up social convention where older generations are extracting rents from new graduates? At any rate, the effect seems pretty clear to me:…
For some companies having to pay interns would just mean they wouldn't offer internships at all.
The reason interns are paid less (or not at all) is that there are lower expectations for interns and other staff usually has to take time to mentor them or check their work.
Maybe not the best example, but if a new paid employee says, "No, I've never used source control, what's that about?" it's a big problem. If an intern says it, you explain it and move on.