A hero is one who forsakes the immediate, including his/her own life, in the name of achieving something of transcendent value.
Grand simple theory: the mechanisms of life should not become the goal; that is confusing the means and ends. The goals (and values) of life should always be intangible, the means tangible. When one inverts that equation, one has a regressive and anti-heroic spiritual outlook which favors changing the means one uses in order to preserve tangible items, which results in a neglect of any future change or any design change for the human effort. Ultimately this causes stagnation and infighting in addition to the obvious lack of ambition or forward evolution.
Heroism is an antidote to the dominance of the tangible because it upholds the idea over what currently exists, and what feelings and needs the body and mind have that come between the current state and something better. If a society has heroic goals, it continually becomes better at being what it is, and thus becomes one with its external environment, and does not fall into infighting for dividing up what is because there is always something better to be achieved, and the process of achievement itself is viewed as favorable.
The last heroic societies known to Europe were Greece and Rome, but before them, in India, the Vedantic civilization invented many of the epics of heroism. In our current modern society, with to our mind nature appearing totally conquered, there seems to be no need for heroism, as we would rather wrangle over internal issues than focus on the future.