In America, most people don’t live near a city center big enough to warrant an intercity train station. 75% of Moscow’s metro area lives in city limits. There is no US city like that. For DC, it’s less than 20%. Also, in America 88% of households own a car, versus 55% in Russia.
I can be at my local airport (Baltimore) in less than 30 minutes, and be seated in another 30 minutes if I’m traveling early. If I lived in real America, somewhere like Kansas City or Buffalo, it’d take like 15-20 minutes to get from parking to the airplane.
To your point, I thought Columbus, OH, would be a good candidate for a large city limits population. According to Wikipedia, "Columbus adopted a policy of linking sewer and water hookups to annexation to the city." This means that Columbus proper includes low density areas which would typically be suburbs outside the city limits of most cities.
Even still, the city population was about 880K in 2018, with a metro area of 2.4MM. So even in a US city with a somewhat aggressive annexation policy, still only about ⅓ of the population lives within the city limits. And Columbus has no passenger trains, anyway, neither intracity nor intercity.
I can be at my local airport (Baltimore) in less than 30 minutes, and be seated in another 30 minutes if I’m traveling early. If I lived in real America, somewhere like Kansas City or Buffalo, it’d take like 15-20 minutes to get from parking to the airplane.