Its the vendors that scare me. They smell blood (money) and will be constantly whispering in the governments ear - they will (unfortunately) appear as "experts" to the government.
Adding reinforced doors to airplane cockpits. It becomes significantly harder to hijack an airplane so it's not just for show.
Security theater can be useful. EX: Add fake video camera's in plain sight at a bank and hide the real ones. People act like they are being watched and feel their money is safer but it's harder to disable the camera's.
The value in security is often to prevent people from trying to attack / break in, or to make harder / take longer to do so, or to make people feel safer. While security theater only does 2 out of 3 it's not quite useless.
