It's impossible to judge a man past and present based off of a 45 second clip. If anything, I see more sleep deprivation now vs. then. Other than that, you can still see the cockiness, just with a younger voice.
I mean the clip was of him taunting Pride that his UFC boy is going to win their tournament. That's the Dana White I've always acted like I knew.
Listen to the clip of him commenting the Chuck/Jackson fight and tell me that's a different person. That would have been only days/weeks/months following the clip you used as an example. Him repeating over and over how "Chuck getting his ass handed to him was not part of the gameplan" "Chuck's not executing the gameplan" "Chuck getting punched in the face is not the gameplan"