I'm not saying the calculations are wrong. I have no time to check their sources, and no knowledge about them. What I do know is that there can be specific safety regulations that drive up the costs. Again, see fire safety at german construction projects (which btw should have no connection to subway lines, apart from the station). Apart from that, stepping away from safety, there can be differences in the costs of obtaining the build rights, and vast differences in how the contracts are created. There can be corruption, there can be ineptitude, there can be the common failure of an unregulated market.

It it even worth arguing that? I'm saying "specific things can drive up costs, safety regulations for example". If I understand you right, you were saying "specific things drive up costs, I call it social technology". Why does my position even conflict with your theory? That fits together, just view those regulations as a factor in your social technology model. The sole position to give up would be "safety regulations don't drive up costs at all", which is ridiculous anyway, thus not a hard loss.