Well, the thing that NuBSG (the poster child for modern dark n' gritty science fiction) did, though TOSsers are loathe to recognize this, is that it maintained an element of hope, however faint at times.
It was dim, it was distant, but it never died. And that is why it worked for me. No matter how dark, there was always that element, that if only we hang on...if we live just a little longer.
I find that more convincing than the "shiny, happy" version of hope that TOS-BSG maintained.
TOS-Trek wasn't about survival during adversity, though. It was about a civilization in it's prime, a galaxy full of possibilities and seeing what's out there with a brave face and curious mind. And when necessary, leaping into danger and fending off threats against long odds.
Abrams nailed that perfectly.