If thats the case... and no one other than superpowers can afford to build missiles and there aren't any to threaten us, what are we building them for? Terrorists won't be able to.
I think that there's one superpower left, and that's us. Actually, we're not building any more, we're maintaining them if not dismantling them. We've agreed to, or announced unilaterally, a very deep cut in our overall ICMB arsenal. We're paying Russia to keep a lookout on theirs, while we help dismantle them. As you point out, it't the rogue states, or China, that will be able to attack US possessions with a cheap, dirty missle tossed 1,000 miles. That's our new threat, and that's what we should be studying. It'll be the next war, not the last one.