It seems someone dies or nearly dies every time this century. There's the 2003 story here. I recall that an Italian may have died in 2007. An American was hit by a truck and died in 2011. And this year, 2015, a French rider from Loudeac was found dead by the side of the road between Loudeac and Carhaix.
Nevertheless, PBP is so ingrained in Brittany especially, I don't foresee them ever retiring the event. Rather, the bigger risk of riders' negligence is closing or severely limiting participation for those who have not done the qualifying brevets in France, which was ~50+% in 2015. These riders could arguably be excluded on the grounds that they do not sufficiently know and/or do not respect the French traffic rules and signage, say. My sense of this is based on relatives, newspapers, and people whom I meet there.
I do see more liability mitigation on the part of the organizers each time, perhaps at the insistence of insurers. That's a good thing. They do their part. I say to do our part, don't give a reason to be uninvited next time.