It doesn't matter since Southern California isn't a political unit. Any significant rail improvements would require state and federal funding to be feasible.

First you use the argument that the entire United States is not as densely populated as Germany, which I pointed out is flawed. Now, you're trying some political tangent. First, we should agree that it is worth, or not worth, being built on technical merits then we can discuss the politics that follow. Jumping around in a scattershot discussion is not effective, unless your goal is to derail the conversation. Pun intended...

I thought we were discussing why Germany has better passenger rail infrastructure, not whether there are technical merits for building it.

You were, he's looking for an argument.