I have to side with Winchester here Pal. I have a good friend who hunts with a Quackenbush. I have shot his rifle and it is as fine an air rifle as I have seen. However pushing it means range to me. My buddy uses his at NO MORE THEN 35 YARDS. This is to keep enough velocity to get a pass through lung shot. He hunts as your video showed from a tree stand and gets lots of shots under 20 yards. In this range group they are plenty effective. The real trouble is moving out past 50 yards as these things do not carry velocity well at all. But that is cool. He gets his life back after a stupid mistake when he was 18 with a 15 year old girl. He would rather shoot a 30-06 so he doesn't share your belief that Air guns are that great. He has one he hunts with it , he describes it as being about equal to a .410 slug out of a shotgun but more accurate.
I would say his rifle is most likely equal to a .45 acp round out of a carbine like the Marlin camp out to 50 yards. Yes the big bores will do more. That .50 will kill further then my buddies .357. It takes a LOT OF air to get that bullet moving. I think Airguns are cool. the .357 with a bullet mold and few spare parts would be a great all around survival gun. No need for powder, wads, primers etc. Just scavenge lead mold and shoot. I have lots of respect but lets not try and compare them to similar caliber powder propelled weapons.