For some specific models like the Camry they did not significantly increase in weight but massively increased in lethality so it isn't only weight, but weight is likely to be a part of it.

The other thing I would blame is how distracting so many car features are distracting now, and a lot of people become reliant on automated warnings that are going to alert them a lot later than if they were just paying attention. The screen in the console being flashy plus not really paying attention is quite the combo but if I understand correctly it wouldn't get counted as distracted driving like with a phone.

i have a hybrid sedan. it weighs 5k lb. this is heavier than any of the 2500 and 3500 trucks i've owned (which, granted, are old, but still)