That could be true as most of the Presidents nowadays are already at their golden age, Im not just talking for US but definitely all over the world. That is why in the case of Biden, most of the democratic voters are expecting that he should not seek again for another long term. But Biden I think is determined to run again, regardless of his old age (the oldest president in the history I guess) but I just hope his physical and mental health will not be triggered by the time the Presidential campaign starts.
If Biden is running against Trump, then age won't be one of the campaign topics. Because there is hardly any difference in age between these two. But that will be an issue in case Biden is running against DeSantis, or Kamala is running against Trump. I have already posted my opinion. I am against discriminating people by age. If someone is competent enough to become the POTUS, then he should have the opportunity to do so. Age, color, race, religion.etc should not matter in this case. As long as Biden is medically fit, I don't have an issue.