USA politics - NOT amateur radio

In no way can (or should) I express views on how the people of the USA should vote for their president in November. They will rightly vote for the person they choose. But I am puzzled. Let me explain.

1. Firstly, I am surprised that their choice is really between two very old men. In a country as vast as the USA, surely they could have found candidates that were younger and sharper.  At 75 (as I am now) there is no way I'd want such high office.
2. Secondly, about half of the USA supports Mr Trump. Whatever your views I have yet to find anyone outside the USA who likes him. I really do mean anyone. Not one person has said a positive word. I have spoken with lots of people from the USA in the last few years.
3. Thirdly, I am puzzled that so many people want to be led by a billionaire who seems to want to be all powerful.

No, the USA puzzles me.