At least in the US, the danger from newer cars isn't more powerful engines, it's that cars are bigger and tend to weigh more than they did 50 years ago. Some of it is quality-of-life changes (AC compressors are heavy), some of it is a trade-off made for safety or crashworthiness, but a big chunk of it is because Americans have largely opted for big cars -- SUVs, pickup trucks, minivans -- to the point that the 3 major American auto manufacturers basically don't sell anything smaller than a family-size sedan[0].
[0] As someone who loves smaller hatchbacks, this really grinds my gears.
I really doubt the difference between a 1700 lb (1980 honda civic) and a 5600 lb (2020 escalade) vehicle matters that much in a collision with a pedestrian. from a conservation of momentum standpoint, the 1700 lb car already weighs so much more than a person that the additional weight from a modern SUV has little effect. either way, the vehicle plows straight through with minimal loss of velocity. the bigger issue with SUVs is the clearance; a pedestrian is much more likely to be run over by and SUV, rather than thrown over the hood of a small car.
That represents a greater danger in vehicle-vehicle collisions, but I doubt it's anywhere near as a large an effect for vehicle-pedestrian collisions.
It's possible, though, that the larger vehicles represent a greater danger due to poorer visibility. I don't have enough experience driving a contemporary truck or SUV to know the driver's experience, but I do know that, when parked along the street, they present a serious visibility problem for pedestrians compared to coupes and sedans.
[0] As someone who loves smaller hatchbacks, this really grinds my gears.