Money presumably. The fact that it's comically expensive in per mile costs, in some cases nearly $1 billion/mile[1] in LA, in addition to maintenance costs woul

Money presumably. The fact that it's comically expensive in per mile costs, in some cases nearly $1 billion/mile[1] in LA, in addition to maintenance costs would just nuke the ideas. [1]https://www.citylab.com/transportation/2018/01/why-its-so-expensive-to-build-urban-rail-in-the-us/551408/ https://www.citylab.com/transportation/2018/01/why-its-so-ex...