Government has gotten us all involved in an endless war of attrition in which the average person has almost nothing to gain and everything to lose. If the priority was really to keep the population safe, things would be handled very differently.
People can conspire, people can be crazy, or unhinged. Columbine, for example. And even if we accept that terrorism is a reaction, they exist in many countries and would inflict more harm if they could. Terrorism is not a thing which only threatens the US, it exists in Europe, Africa, Asia, the middle east, etc.
But yes people will have to come to terms with how to deal with the issue of privacy (secrecy) vs openness (accessibility) How it's managed will change over time, surely.
These questions must be weighted by each person for him or herself. I've chosen for some nicer car insurance. I still don't have nuclear terrorism insurance. I still sleep well at night after working in defense in this area and having friends working on these very issues.
But the solution to "someone might steal a nuclear weapon" is not "spy on everybody in the world" -- the solution is to secure the nuclear weapons. Which is a thing governments do that nobody is objecting to and that has nothing to do with mass surveillance.
After WWII, the US government and foreign policy got reconfigured in such a way as to assure the United States could defend itself from a nuclear superpower and to have access to the resources to re-fight World War II.
The original goal in all of the above was to keep the population safe. Things have evolved a little since then, however.
This is fundamental, and this point needs more airtime than it gets. Terrorism is a real threat. It is a challenge that our institutions are struggling to deal with. But the threat that it poses is tiny compared to the threat of powerful government, a troll that goes back to the beginning of civilisation. We must not let the focus on terrorism distract us into relinquishing defenses against the greater threat of powerful government.
Advances in technology make privacy more important than it has ever been. Without privacy, there is vast opportunity for government to reach deep into our lives in the name of enforcement.
Government of the people has an obligation to find ways to combat terrorism that are compatible with the controls we need on government. If we don't hold the line on privacy, government will increasingly shift us towards serfdom.