Even in his prime, Cain exposed himself to getting caught cause he is somewhat wreckless and likes to bang. Got caught by Kongo, kod by JDS, stunned by JDS in 2nd fight, clipped several times by werdum...don't get me wrong his chin is OK, it's just that he s fighting beasts , men much bigger and powerful than himself. Even granite chins like hunt and Nelson get finished at HW, still Cain's chin isn't amongst the best and DC, for sure, has a much better chin. Other problem is his awareness, meaning he doesn't have that scared look on him which sometimes DC has when you see him kinda dodging and backing away from big power, putting his lead hand forwards. If you look at the stipe fight DC was very wary whilst striking at range: quick nasty jabs and 1-2s and when Stipe thinks he's walking him down, boom DC explodes and kos him cold unexpectedly. Even with Rumble, same thing....very quick in and out exchanges. Cain, on the other hand, is more of a savage and does not usually back off when he feels huge power coming at him. His wrecklesness and his ordinary chin in both training and fighting might be/have been his demise.