I agree things are better than even, but let's not forget that's on average.
Many people still suffer, and even the luckiest of us can see it.
People just aren't wired to think about things in terms of population statistics.
> people talk of the current world and time in negative tones
Are you sure they aren't also considering the trend that we're on?
Things are good overall, but China and Russia are not functioning democracies, and most powerful countries are trending away from democracy.
> it is cool to think negatively of the world
It is cool to be concerned about others who are suffering (and maybe even a status symbol for some), and that concern leads to negative feelings.
No one complains about the state of the world insincerely...