A high profile person calls attention to whatever they espouse because they are high profile.I just don't see how a so called high profile person would help to encourage the public to consider using trains. As much as I enjoy Amtrak, outside of the NEC Amtrak just isn't a viable option for most and there are other more efficient travel options avaliable.
Because "Hey, So-and-so rides Amtrak. Why don't we try it?" is an effective ad for train travel. But as others on this thread have pointed out, high profile people who ride Amtrak don't advertise it so they don't get mobbed.
Why don't more high profile people ride the train? They do. They just don't tell anybody.
Also, there may be more efficient travel timewise, but there isn't one more enjoyable. Even first class air passengers are not encouraged to get up and meander around. On planes and buses, you're stuck next to who you're sitting next to. On the train, worst case I can escape weird seatmates and crying babies by heading to the lounge or club car. Best case, I get someone willing to share the joy of the view.