Only psychos would WANT to live to be a thousand years old.
Gates, Soros, et al.......................
I think most 100 year olds would say heck no to another 900 years!
The sci-fi movie Zardoz did an interesting, through shlocky, job of addressing this scenario.
After some type of apocalyse, a group of elites, who call themselves The Eternals, do indeed succeed in becoming immortal. The literally cannot die, even by their own hand apparently (though have they tried cutting off their heads?). Great, eh?
The flip side is that they become so bored with life that they end up wishing fervently for death. Once they do end up becoming mortal again, they respond by committing suicide as quickly as they can.
The rest of humanity are called Brutals, and do indeed live a life that is brutal. They are little more than cave men who can talk.