This is not really true, at least for the northeast corridor. Amtrak is the fastest way to get from DC to NYC for example due to traffic in the city if driving or taking the bus, and the distance from the airport (LGA or JFK) to the final destination in the city if you're flying. I take Amtrak somewhat begrudgingly because it often can be way more expensive than flights which are subsidized generally speaking over passenger rail these days, because it's simply faster.

And I honestly don't know what adventures people are talking about, most people keep to themselves. I've had more stranger experiences on flights than I have on Amtrak but maybe it's different in the West Coast.