One of the most egregious issues with the second avenue extension is that the underground portion is way larger than comparable systems. A large part of this is backoffic space (which should be overground and consolidated, like everywhere else), which no minority interest group is interest in. And you can see that: In the next Phase they have reduced the backoffice space (which no passenger will ever notice) due to cost pressures (saving over a billion, I think) and no one complained.The same is true for many other examples.

This is also noticable elsewhere. When looking at german planning, they reference other german projects and rarely projects of the sourrounding countries, and thus often don't notice the lessons learned there.