"That hope died with the selection of yet another, white, male, oligarch as the opposition to insanity but specifically chosen to minimize any change to the system."
Old Joe realizes that his legacy is tied to the future, not the past. His alleged "dementia" is not strong enough to overcome his realization of the fact that his time is limited and short. As Trump might say, "What has he got to lose?"
Biden knows much about death and tragedy. He sees our republic's trajectory toward demise and intends to change that trajectory, if it's the last thing he does. And it may well be.
“We shall nobly save, or meanly lose, the last best hope of earth.” A century and a half later, those prophetic words ring more true than ever. I think Old Joe hears them quite clearly, not as a death knell, but as a clarion call.