This good article brought up some good points. Other than the obvious one about not placing crash dummies in the rear seats in American crash tests, it mentioned front seats collapsing back putting rear passengers in danger, which is something I hadn’t considered.
I’d also like to add that the increased rigidity or strength of the front end of vehicles, which is done for safety or to look better in a crash test, exposes the rear seat passengers to greater forces in a front end crash. It the past it was common for only the rear seat passengers to survive a severe crash. Today this rear passenger survival isn’t as common.