I blame the now-common blind spot warning systems. A lot of people have grown to rely on the blind spot warning and don't bother to check the blind spot any more. And since there has never been any government standards or third party verification tests for these warning systems, they are a real mixed bag as to how well they work. And it seems like many of these warning systems (including front and back auto braking systems) can't detect bicycles.

But anyways, never ride in anyone's blind spot.