Plenty of people use rail in the US just for carrying goods instead of people. It turns out trains are most efficient at hauling large loads with high tolerances for latency, which humans are not and do not have.
While in Spain for several months it was only economical for me to take a train a single time. It was several times more expensive than the alternatives in every other case. This left me either flying or bussing.
In Stockholm it's actually cheaper to take a bus to the airport than the train, and that's just local travel.