Political parties do die. They don't die often, but even in the United States they sometimes go belly up. I think that the Republican Party has become stuck in an ideological and demographic trap of its own making, and I'm not sure that it understands the seriousness of the situation. It's Congressional deficit is greater than any that the Democrats have faced since 1931. It's struggling to maintain its share of a part of the electorate that is steadily shrinking, and it has failed to make serious inroads into any other demographic.
For one thing, the last time a major party died was in the 1850s, and its death gave rise to the Republican Party and the Civil War. To say they "don't die often" is a bit of an understatement.
But beyond that, I'm not sure how useful it is to use a party's demographic shortcomings to describe its prospects for overall success. Yes, the GOP is at a low ebb right now, but not necessarily because its unpopular with Latinos or women. It's pretty much unpopular across the board, as this graph of party self-identification shows:
But that won't last forever. At some point, Obama's approval ratings will drop significantly, either because the economy fails to rally, or because of a scandal or some kind of screw up. And the GOP will look relevant again. That doesn't mean they'll be the majority party again any time soon; that may take decades to achieve. But they'll be back. They'll probably make some gains in the House in 2010, although I'm not sure about the Senate. And when their stock begins to rise, they'll start looking good among various demographic subgroups, too.
Just remember where the Democrats were in 2002. It really didn't seem like they were on their way back to unified control of the government within six years.