You guys have it all wrong. Its because things are so good now that we need our escapism to paint things the opposite because most people can't comprehend things going to pieces. Its why the little pockets of it that crop up here shake people so damn much. But people like to think that some fictitious bs zombie stupidity is how things would be. Not likely at all. People are just being delusional and its escapism from the hum drum 9-5 things aren't so damn bad after all lives people are living.
Seriously, anyone who thinks now is more full of strife doesn't know jack shit about history, even pretty recent history. Could that change, pretty much in the blink of an eye? Yeah, but that hasn't happened for most, while progress slowly marches on. I think this is why people are so seeking apocalypse, despite the confluence of all these minor things and the countless cataclysmic things that we can't do anything about (supervolcanoes, planet-killing space events, etc), humans really are actually holding together pretty damn well.
As for scientific advancement, there's still a lot going on (honestly, maybe more than ever), but the directly tangible impact is being lessened. We're learning some responsibility in using things because our better understanding of them has changed us. We're butting up against very real limitations with ourselves as well. Space flight is still tough as hell, the only reason it seems different is that our understanding of just how hostile it is has changed how we approach it. Seriously, go read up on what we now know about just spending a few months in space and then maybe connect the dots to why going to Mars isn't just about getting the money to go. And Mars is actually pretty ridiculously easy compared to what's beyond.
If anything, those were even more evident in the 1960s when Star Trek was created, and more prevalent in the 70s when it was in syndication, and still progressing with cold war tensions in the 1980s for TNG.
Not much terrorism going on in the 1960s, and other than North Korea's angry foot stomping, not much threat of a nuclear war today.
Not much terrorism in the 60s? JFK? Ever hear of the Weather Underground? Black Panthers? And of course the people/groups that were the reason groups like those became so radicalized. CIA and FBI (read up on their opinion of the civil rights movement and people like Martin Luther King Jr.). That's just a minor part pertaining to the U.S., there was a lot of shit happening just about everywhere that would be worse than the average "act of terror" now. A hell of a lot of it was being done by our government (Bay of Pigs anyone?), although certainly not anywhere close to all of it.
Seriously, even with 9/11, this has been a pretty damn mild time. Just because compared to the 90s it had some bigger events closer to home doesn't change that. Yes there's still a lot of awful terrible things being done in the world, and at times you see glimpses of things from the past, but people really need history lessons to appreciate things.