Comprehension fail.
If you don't vote, nothing happens. If nobody votes, the system does indeed die. (Of course there is plenty of room to debate whether that is a good or a bad thing, which rather depends in what replaces the dead system).
and you present both a logic and a comprehension fail - impressive!
IF nobody voted, the system would die - but that doesn't happen, so it doesn't matter. IF the sun exploded, we'd all be dead... IF all the oxygen on the planet turned into chlorine gas, we'd all be dead. IF every tuesday was mandatory blowjob and cheese cake day, i'd be much happier... but that's never, ever, ever going to happen, so basing an argument on that happening is pointless and stupid.
as to the original question:
simply put, we're all born against our will into whatever country we live in - and while as a member of the species there can be a compelling argument about how we all have at least some level of obligation to "play nice" within society as a whole for the good of collectively maintaining human civilization, that doesn't mean we have a moral duty to take part in social or political systems that we consider inherently and insurmountably against our own interests.
i do not vote because the entire US political system is fucked from the ground up. it works insofar as the country hasn't imploded on itself, but nothing about the US political system in any way represents my morals, ideals, or interests.
yes, democrats disgust me substantially less than republicans do and i'll always prefer that a dem gets elected, but i just don't give a shit enough about the current or future state of the country to masturbate into a ballot box every few years.
elections in the US are essentially determined by zealots - whichever party either gets their base the most pissed off to bolster attendance or whichever party's base has gotten the most pissed off by the other party that year is the one that wins, period.
unless voting in the US has a massive structural revamp and becomes both convenient and compulsory (which it should do, by the way) individuals or even giant teeming masses of individuals voting or not simply doesn't matter, the system is specifically built so that it doesn't matter.
as george carlin said: those who do not vote, and thus are in no way responsible for the state of the political system, have the most (and indeed only) right to complain about things.
[youtube]http://www.youtube.com/watch?v=HeMGqTwWA6U[/youtube]