The problem is there so much ego when people get into power they want to stay there forever. Same thing happened with Ruth Bader Ginsburg, folks knew that lady was too old to still have that position. At some point we need new faces, younger faces, otherwise a large chunk of the country will never be energized voting for yet another old person in power. It's become the same old song and dance.
The minimum age is 35, but there's no maximum, and we've never had a 30 something President in the history of the country. Nobody is excited to vote for Biden, it's "block Trump." Cool, but why should I care about Biden? Plenty of Americans are asking themselves the same question.