Typically PD as an exercise is a one-time case. PD in continuous cases has been pretty widely discussed over the past few decades: it's been awhile since I've done game theory so I'd love to hear some thoughts on someone who's a domain expert.
If I understand correctly, the "big deal" is about reframing the question in an evolutionary game theoretic perspective, though I don't think the revelations themselves are that groundbreaking.
