If you had read the Challenge article that came out at the time, discussing lethality in RPGs, you would know that it's not so far-fetched for some one to survive lots and lots of gunshot wounds, especially in an era where competent medical attention is usually only minutes away. Indeed, for the most part, killing some one outright with a gunshot should be accomplished on a critical result. Anything less just hurts a lot...
Let us also consider the environment the game was thrown into. How many players like to see their characters die in the first encounter to a lucky shot? Considering the amount of FUD generated by dying during character GENERATION, I should think you would be a little more open to the idea of surviving an encounter or two too. Really, did your character SUDDENLY become a fragile idiot, just because you are playing him at this point in his life? That would be kind of insulting, to think that players are all idiots, because they can't keep their characters alive more than a few days of taking control of them.
I think it's pretty reasonable to allow a character to survive past his first encounter more often than not. Not too many games DON'T give a player some kind of edge, to allow them to survive their first session and beyond. Who wants to spend hours ROLLING UP characters, to have them die in the first few minutes of the game? How realistic is it that, every step of the way, the protagonist party loses a few members, but the exact number of losses is always made up at the next break in the action?
No. Realism, playability, and thrill-seeking ALL demand that a PC can take a lickin and keep on tickin. Sure, the sheer stupidity of picking fights with streetgangs should get your butt handed to you, but how many would watch a movie or read a book in which ALL the central characters were killed within 5 minutes of appearing on the screen, and mystically the replacements always continued whatever mission they were on, even when none of the original members were still there?
Your 12 hits example is a bit misleading. That's 12 damage points, something that can EASILY be accrued in short order, and there are plenty of steps before you get there, in which that limb becomes less-functional. Shoot yourself in the arm with a .22. Does your arm fall off? Probably not. Assuming you missed the important blood vessels, you could probably stand a dozen MORE shots from a .22 to the same arm. That's a lot more damage than 12 hits, I'm pretty sure.
Like any game, there is a trade off between stark realism and playability and fun, and no two games do it quite the same way. I think TNE did a reasonable job of striking a balance, like most other games have done. If you don't agree, then by all means, use your favored system. Nothing can appeal to everyone all the time.