It seems to me as though this "why to live" must transcend one's own life in order to have this effect. From this perspective, your epidemic of meaning might reflect a consensus world-view which is overly individualized.
"My formula for greatness in a human being is amor fati: that one wants nothing to be different, not forward, not backward, not in all eternity. Not merely bear what is necessary, still less conceal it—all idealism is mendacity in the face of what is necessary—but love it"
For him there were no transcendent values, ideologies, gods, what have you. People weren't individualist enough. To him it wasn't about latching onto some cause but to, in his words, become who you are. Affirm your own will and say yes to the world even if you, like in one of his thought experiments, lived in the worst world imaginable, on repeat, forever.
He viewed nihilism as one of the largely inevitable outcomes of the failing of transcendentals to provide meaning.
Thus he attempts to overcome modern ennui via the construction of a strictly immanent conception of the world.
Labeling him a “nihilist” is misleading. Owing to the conflation of nihilism with a dour, depressive outlook, many are surprised to find out that his writing is in fact consistently joyous.