The airlines killed the passenger service by rail.
The highway system killed the freight rail service, in addition to the fact that the national rail system was run down by heavy usage during the war, and the major railroads, particularly the NY Central and Pennsylvania, and their neighbors in the NE, deferred maintenance. Union work rules didn't help.
Both airlines and road transport were heavily subsidized, something the railroads didn't get.
We certainly live in different times.
Tom Friedman expresses his ideas in Hot, Flat and Crowded and the need for a Green revolution
Book Passage - Hot, Flat & Crowded: Why We Need a Green Revolution -- And How It Can Renew America.
He incorrectly states that the government invested in the railroads. They didn't after World War II. The government invested in airports and traffic control, and highways.