Maybe if I speak slowly you guys can get this. A falling cinder block can injure any number of things on the way down, but every time it does, it subtracts energy from the equation. Each collision is an energy sink. That energy is spent doing the work of breaking something, thus it is not available for accelerating the falling mass downward, therefore the falling mass will slow down. The more things that are broken, the longer it will take.
Put the other way around, if falling mass arrives to the ground in free-fall time, then it did not injure anything on the way down. If falling mass arrives to the ground in just over free-fall time, then it did not injure very much of anything on the way down.
Thus the scenario you all want to imagine is trying to have it both ways. You're trying to say that falling mass damages everything, so much so that very little is even left of the whole building, yet damaged so little that it was able to arrive in just over free-fall time.
It's just at odds with itself.