Dieing for your country has changed too much since, in Horraces' words, it was a 'great and noble deed'.
Since industrialization (lets say 1914), wars have aquired an all-encompassing destructive capacity. Much is left to chance and instantaneous, widespread, unavoidable, unseen killing. They are no longer good sport, cleansing or able to offer survival based on skill.
Also, with rising living standards comes a better educated and enfranchised public who can question and direct government in a more effective way. Going against this shatters public condifence and trust in government to do the right thing by them. THis results in the gvt falling and apathy soaring (eg chronic cynicism over policy motives). Vietnam is the obvious case in point.
We're also living in an interconnected world where the state's capacity to make huge differences to our lives is eroding. Previously, we could be shielded from the world, become totally self sufficient, and have the state as our only spokesman and protector. Now that's largely obsolete.
In short, the state's ability to persuade us to die for it has been severely undermined. Unless there is a very clear connection with our immediate personal security (or economic prosperity in the case of professional soldiers), I doubt that many of us would unconditionally die for the country.