That’s because weight is the enemy of performance, and higher end vehicles use as light of materials as they can. Occupant safety is mostly a function of the passenger cell on such vehicles, not the fenders or other bodywork. Though that said, they shed a lot of impact energy through that same bodywork disintegrating.
Mind you, they *usually* do better in high speed and other crashes in terms of occupant safety than your average family sedan, despite ‘looking’ worse. That’s not new - go look at Barbra Mandrell’s crash in the 80s, where her Jaguar sedan went head on at highway speed versus a GM pickup that crossed the median. She walked away, the driver of the ‘big strong sturdy truck’ ended up with the engine in his lap and died, despite the Jag being smaller and actually looking like it came off worse in terms of body damage.
More than a few of the collisions often resulted in fatalities to the lower sport car vehicles, including the occupants of the lower vehicle being beheaded.
In this scenario, if I have a choice of being in a head-on, I'd opt for being in a higher 3/4 ton truck any day of the week, as opposed to being in a low profile vehicle.