Why do us Americans tend to prefer old people as Presidents all of a sudden?

[Vice President Christian Man]

I think it has to do more with policies than age. American's as a whole, Democrats in particular are comfortable with the establishment who is promoting idea's that have been orthodox in the party since at least the 1970's (and represented by people politically active since the later half of the 20th century), while rejecting newer and in some cases more progressive ideas represented by mostly younger candidates (the notable exception being Sanders). I believe that our politicians are often about 20-30 years behind the mainstream opinions of voters in most cases barring congressional landslides because of the lack of term limits in our country. I think as soon as the old guard retires, we'll likely see younger presidents because their ideas are different than the one's that have been pushed by older politicians. This is true in both parties and while the GOP is transitioning to a new orthodoxy, the Dems haven't transitioned yet but the transition may occur sooner rather than later (assuming the voters are going to choose a candidate with different views) with politicians such as Yang and AOC being as mainstream as they are within the party.