To add to this, I've read accounts that US Presidents suddenly needed to be charismatic to compete meaningfully after the debates started being televised. So even being charming had not always helped one win public office.

I recall a story about Calvin Coolidge, who had earned the nicname "Cool Cal" for his standoffish attitude, about a dinner party he attended. Another guest bet him they could get him to say three words to them by the time the party was over. He didn't say anything in response, then found them at the end of the party and said, "You lose."