You compare america vs other even older cities in other developed european cities delivering new rail lines far faster and cheaper and those kinds of excuses just doesn't pass muster.
More context: https://www.citylab.com/transportation/2018/01/why-its-so-ex...
they specifically call out san francisco's line as having reason to be expensive, but point taken—America has broader problems developing rapid transit.
Everything you say should apply to Madrid or Barcelona Spain, but worse as the city is older. Yet Spain manages to build subways for a small fraction of the cost.
It’s certainly not an easy engineering task but it’s made even more complex by regulations.
At some point we need to understand the trade offs that come with regulations and either redesign them to enable large scale infrastructure projects or accept the fact that such projects are just not possible in the current framework.
So for eg environmental regulations to deter coal plants are fantastic because they encourage the alternatives. But regulations that prohibit anything seem as useless as no regulations: we need to generate power somehow.
As soon as you start digging underground you find a whole litany of old pipes, wires, mains, etc that do not appear on any drawing. You're unsure if they're in use or not, and some of them are so old that just pulling the earth away from them causes them to fail.
There's more to it other than politics. These things are hard to do in established cities, especially at the shallow depths that muni operates at.