I haven't stepped on a plane since 9/11 due to the stupidity of the new regulations. In that time, I've taken 3 cross-country (Utah to east coast) Greyhound trips and one drive that would have been normally taken by plane. Two of those situations were for end-of-life situations for grandparents.

I've investigated trains, but they cost nearly as much as a plane and take almost as long as the bus, so why not take the cheaper option?

I'd personally refuse to take any job that required air travel and wouldn't let me drive in lieu of the plane. I'm sure that would limit my professional options, but I'm willing to put my money where my mouth is.

Try crashing a train into the White House, or a nuclear power plant, or hijacking it to Cuba, or any of the other stunts people try with planes.

Trains are intrinsically less interesting to terrorists. Not uninteresting necessarily, but much much less interesting.