Did the likes of Tyson/Holyfield have immense confidence in their chins?

I see some fighters like Wlad, Haye and co take their foot of the peddle at times when they are in their opponents punching range and they would only land their punches when they are immensely confident that the other fighter will not retaliate.

But with Holyfield and Tyson, you can see the immense confidence both these guys have in their chins, they are not scared to get hit at all, both guys back themselves to the hilt to take their opponents best shots and both guys are the type to take punches to land their own. In fact Tyson had so much confidence and faith in his chin that he decided to lazily do away his defence for the remainder of his career. Very legendary attributes in my book that are missing in the current day fighters today.