The problem with all these measures is that they're only effective if we guess the plot correctly. Defending against a particular tactic or target makes sense if tactics and targets are few. But there are hundreds of tactics and millions of targets, so all these measures will do is force the terrorists to make a minor modification to their plot.
It's magical thinking: If we defend against what the terrorists did last time, we'll somehow defend against what they do next time. Of course this doesn't work…This is a stupid game; we should stop playing it.
But we can't help it. As a species, we're hardwired to fear specific stories…and we want to feel secure against those stories. So we implement security theater against the stories, while ignoring the broad threats.
What we need is security that's effective even if we can't guess the next plot: intelligence, investigation, and emergency response…
Finally, we need to be indomitable.