All of the excuses you will hear (botox, rich people's attempts to appear ageless, chemicals, cosmetic surgery etc) are also reasons why this is totally plausible. Leaders of nations have used body doubles since forever.

Wikipedia: The political decoy is an individual who has been selected because of strong physical resemblance to the person being impersonated. This resemblance can be strengthened by plastic surgery. Often, such decoys are trained to speak and behave like the "target".

It's such a strong urge to fight and I am too weak, I always do this in this particular forum but I must do it again (i must bring up metal gear solid). In MGSPW2 it is shown what lengths the secret society can go to create clones of a person. Like trauma, hypnosis and genetic engineering through nanomachines to even make a person believe another man's memories and experiences are their own.

The main character in the series' name is Jack, after a mission he gets awarded the title of "Big Boss" which he refuses. He defects but they still use his face and that title in propaganda campaigns for years! So it was important for the secret society to try and duplicate him is any ways they could.

As for Biden, I believe that these are pictures of two different people. They look very similar and we get this phenomenon often throughout history. No, I have no certainty and I cannot say much besides that Biden totally could be a decoy. Or not, IDK. It's possible.

EDIT/ Addition: The main reason I believe this is a decoy is that the ears are at a different angle as well as being a different shape. His skull is not the same shape either. I also hadn't mentioned that the Biden in the left picture didn't have any of the same views as the president we currently have.