The discussion was about the noise makers. If you'd like to discuss pedestrian bridges, please feel free to start a thread about them. I'll be the first person in there saying they're quite feasible in lots of urban areas, and then can even add beauty to city streets when done right. I did not say I don't find them worthwhile, I pointed out that the cost difference for a solution that works (admittedly not perfectly) makes pedestrian bridges "beyond expensive".
This is like arguing that all intersections should be round-abouts. Yes, they're safer than most other types of N-way intersection, and yes they keep traffic flowing much more optimally. But we don't have the physical space for them everywhere we have intersections. So, because of the physical and financial constraints, we use the optimal solution for the situation. Just like we add safety features like dedicated cross walks, pedestrian warning lights, pedestrian control lights, audible pedestrian signals for the hard of hearing, textured surfaces and wheel chair accessible ramps on cross walk entry and exit paths, ridged surfaces that are detectable with a walking stick for the visually impaired, metallic reflective surfaces on the ground at cross walks that can be detected by autonomous vehicles, and so on. All of those systems, in aggregate, save many lives while each one individually may seem insignificant.
