One thing those crash tests into an immovable, non-deforming object fail to take into account is the fact that if an F150 is in an offset crash with something head on, chances are it will be another car. Since the F150 will more than likely have much more mass than the vehicle it’s crashing into, it will dissipate more if the crash energy into the other vehicle.
In the case of the immovable non-deforming object, of course the big heavy truck doesn’t do too well. Force = mass x acceleration. A 5000lb truck going 35 mph into a cement block has a lot more energy than say a 3000 lb car going 35 mph.
In the real world, I’d much rather be in the F150 than a 5 star small car though. Much more likely to be hitting a deforming lesser mass object than a non-deforming immovable one. Of course, if you hit a cement barrier, or large tree, you’re fucked.