The player fell because he had a defender block his shot. Not necessarily because of contact afterward.
The force that made the shooter fall in my opinion had little to do with body contact created by the defender.
In the revised play, now we know it was because of contact afterward.
The initial contact is all ball up top. This doesn't absolve the defender of a foul (I would call one if I thought the defender solidly landed on top of the shooter, for example), but I'll let a bit more subsequent contact down below go when the block is that clean up top.
Now that there was no block,clean or otherwise, does that change things?
If the shot attempt is altered by the contact, if the player is put at a disadvantage in making the shot attempt, I'll call the foul.
The shot attempt was not altered, and there was no disadvantage in making the attempt, so this play can never be a foul?