The only thing that video shows me is that old men move slowly. I saw Obama saying "That oughta do it. Let's go" and patting him on the back as they walked off.
Yes, Biden's old. Too old. I get that.
BUT keep in mind that an administration is never one person. It never has been. And I trust that he will continue to have competent, intelligent, energetic, and yes, younger people throughout his staff.
Trump, on the other hand, will have nothing but sycophants who'll never question whatever crazy shit he spews out.