FWIW, humans have survived falls from aircraft without a parachute, due to the last two reasons. Recalling some of the accounts, it helps a lot if you happen to hit on the downslope of a forested hill with just the right slope.
Those things matter at human terminal velocity (not much mind you) but not at asteroid terminal velocity. Asteroids hit with so much speed that the kinetic energy of impact mostly overcomes the binding energy between molecules and even atoms and the impactor largely vaporizes. This is more true for comets which are looser collections of ice and rock, and more true for larger impactors.
Impactors like that have not slowed to their terminal velocity. They either are small enough to be slowed by the atmosphere, bigger and explode in the atmosphere, bigger still and they race all the way the ground.
