It's irrelevant how Henry came to be better, he was just better.
VanPersie's passing is average, he is slow to execute, his decision making is average and he is weak physically and slow across the ground. First touch and finishing is excellent, movement is above average but not exceptional. He has personality on the pitch and doesn't hide but that's fairly standard amongst the better players.
I am genuinely struggling to see how anyone could even attempt to compare the two, longevity or not.