You have to understand that the average American functions off of lizard brain impulses. It would be probably go like this:
Acknowledging age concerns of the electorate = show of weakness.
Running someone fresh that appeals to this American Idol-esque popularity contest = show of weakness.
Running someone Republicans don’t have their talking-points fleshed out on = show of weakness.
America operates on principles of running someone strong who says they will always be strong and that if they ever become weak while in office and they acknowledge this to be replaced, the entire party goes with them like a tug boat latched to a sinking oil tanker. Trump didn’t win because he’s smart or a decent human being. He won because he exudes baseless confidence like a broken nuclear reactor exudes gamma radiation.