It was getting in the way of profit maximization of the Oil, Tire and Automobile manufacturing Corporations..
And so transportation was privatized ..
https://www.cbsnews.com/news/the-gm-...ally-happened/
https://en.wikipedia.org/wiki/Genera...car_conspiracy
and part of the problem was how, for example in Los Angeles the Redline trolley , publicly supported ,
getting people downtown , did not serve the parts of the sprawl being developed , and so those Developers called it 'Communist'.
[ ref : 'City of Quartz' , by Mike Davis]
So, those Private Interests, pushed to have it destroyed, rather than expanded..
..