It is whether the people who rise to the top and represent the bureaucracy to decision makers are reporting reality accurately, or telling decision makers what they want to hear.
You can lead a horse to water, but you can't make them drink it. The same goes for accepting reality, hence why many choose to live in an alternative reality.
Obviously there are limits, chances are those limits are fairly well described and if they are ever exceeded it will be ugly.
If that's really the case, it's a pretty fucked-up situation. The expected outcome for a politician ignoring technical advice and people dying as a consequence is for the politician to be always blamed. Even when the technical advice was nonsense, what leads to a lot of different problems (including politicians working hard to silence technicians).
I can't imagine what kinds of problems make politicians able to shift the blame onto people that say the structure is not secure, but I'd start searching for corruption at the judiciary branch.
http://www.nyc.gov/html/dot/downloads/pdf/dot_bridgereport15...
Not perfect, but they know what their problems are and have plans to fix. That means having people with a clue, listening to them, and funding remediation. Fortunately, they can fund it now. When I was growing up there in the 80's, things were falling apart.