"A deer can be killed with most any combination if no heavy bones are struck but what is needed is something that will crash through where the going is tough." – Fred Bear; "Hunting Arrows"; published in Ye Sylvan Archer, 1943.
"all else being equal, penetration is the name of the game" – Howard Hill; referring to the success or failure of any given hit; "Hunting the Hard Way"
I've got a collection of broadheads recovered from rifle-killed whitetails, collected for me (still imbeded in the tissue) by commercial game-meat processors in Georgia. Somebody, somewhere is using arrows that aren't penetrating enough; at least on some hits on some whitetails ... and it's more than just a few!
Ed