Herbert Hoover lived from 1874 to 1964. That means that every President from Andrew Johnson to the present was alive for at least part of his life and that streak will continue in this election barring something crazy. Hoover died the same day that Harris was born. That’s 29 Presidents.
Carter is already at 17 Presidents starting with Coolidge and his streak must continue for at least 32 more years which is a minimum of six more possible without a Constitutional Amendment. He will almost certainly break the record even if Hoover gets a couple more.