What is demanded of man is not, as some existential philosophers teach, to endure the meaninglessness of life, but rather to bear his incapacity to grasp its unconditional meaningfulness in rational terms. Logos is deeper than logic.
At any moment, man must decide, for better or for worse, what will be the monument of his existence.
One of the main features of human existence is the capacity to rise above such conditions, to grow beyond them. Man is capable of changing the world for the better if possible, and of changing himself for the better if necessary.
As we see, a human being is not one in pursuit of happiness but rather in search of a reason to become happy, last but not least, through actualizing the potential meaning inherent and dormant in a given situation.
As to the causation of the feeling of meaninglessness, one may say, albeit an oversimplifying vein, that people have enough to live by but nothing to live for; they have the means but no meaning.
You may of course ask whether we really need to refer to "saints." Wouldn't it suffice just to refer to decent people? It is true that they form a minority. More than that, they always will remain a minority. And yet I see therein the very challenge to join the minority. For the world is in a bad state, but everything will become still worse unless each of us does his best.