Also, every time I visit a new airport in the US, it comes to mind how damn near every medium-sized city has a sprawling, fairly clean, air-conditioned airport, with shops and seating, usually open 24 hours. The Amtrak stations in those same cities, if they exist, are usually one-room buildings that close for most of the day. The Greyhound station is nowadays usually just a spot on the side of the road.
Why the disparity? I guess there are just that many more people flying than taking the bus or train? (Built-in security and a generally richer clientele certainly help too, I'm sure)
"Yeah what are we comparing the airport to, home? Plenty of airports are amazing and beautiful.
"
The only thing they compare favourably with are shopping centres. A horrible place to spend several hours or more. Noisy, expensive, usually sterile and ugly. Not my idea of fun. Little or no natural beauty (I gather Singapore and some others have tried to turn this around.)
I have yet to enjoy a train station or bus station more. They are smelly, polluted, greasy, full of pickpockets and worse, usually no places to nap safely without a lookout, and horrendous toilet situations. Maybe there are a few crown jewel stations in very wealthy places that are better than some airports in impoverished places but if you take location into account I doubt you'd be able to come up with many examples.
Compared to every railway station I've seen, airports are 5-star resorts. Bus terminals are even worse than railway stations.