I had to double-check this but it did really take 4 years to complete initial construction of the NYC subway system; however, what's failed to mention in the article is that a plan was approved to build the NYC system 6 years prior. In total, it took 10 years of planning and construction to actually have an initial system in place.
Even though the author failed to mentioned the planning period in that instance, it doesn't take away from his argument that things are slower today in getting large projects built or renovated due to legal and political structures that stop each of these from happening through procedural delays.
I have a great local example of this. My interstate bridge has been in need of repair for the last 30 years, but nothing has been done of it due to so many groups getting in the way. It's been a nightmare and that bridge is very much needed for the local community to stay as strong as it is. I believe the political will to do anything has vanished out of frustration.