Which politicians, exactly? Trump, back during his first term (the rumors about him being on death’s door with COVID were rampant). Biden, for nearly his entire term in office. I remember people insisting Vladimir Putin was on his way out any day now, back in 2023. And there’s an endless parade of rumors about Kim Jung Un keeling over, Ayatollah Khomanie being on the way out, ffs “Castro is dying, get in the boats!” was a thing people said about Fidel from his mid-fifties until he handed over office to his brother Raul in 2008. Pretty much anyone the US government / media doesn’t like gets a scattershot “dude could die any day now” headline from time to time. And the more reactionary the source, the more credulous the allegations.