John Davidson poses the question, "How has Darwinism Persisted?" He believes there to be two reasons in particular which he explains briefly at Uncommon Descent.
I'd like to suggest a third: Darwinism (by which I mean the view that natural processes are sufficient explanations for the origin and diversity of living things) has persisted because it is the opiate of the intellectual elites. It anesthetizes them to the existential pain of a naturalistic world-view which rips all non-arbitrary meaning, morality and significance out of life. Like a drug it gives them a surge of metaphysical pseudo-strength that enables them to cling to an atheistic materialism which might have made sense a century ago but which no longer does. For the man who simply does not want God to exist, Darwinism is a narcotic.
As Richard Dawkins famously wrote, "Darwin made it possible to be an intellectually fulfilled atheist." Unfortunately, the satisfaction that it offers is much like the satisfaction the opium addict gains from his drug. It doesn't really fill the existential emptiness left by the removal of what has been taken away. It merely masks it. Man cannot live without meaning, and atheistic naturalism tells us that ultimately there simply is no purpose to your life or mine. Death is the end. Man is nothing more than an animal with no dignity or worth. Morality is purely subjective. There's no ultimate justice. Love is just a biochemical response. Consciousness is an illusion. Reason is an unreliable tool in the quest for truth.
The intellectual elites are like a bunch of numbed, unhappy addicts sitting around a room seeking to relieve their pain with a fix of materialistic opium, and Darwinism is the best brand on the market. It holds out the allure of an ersatz purpose, incorporating us into the great drama of biological development, it offers us a wafer-thin veneer of meaning by encouraging us to contribute to the well-being of our species. Like those who seek meaning and transcendence in drugs, however, Darwinism ultimately leaves us empty because if we are doomed to perish utterly nothing at all about this life really matters.
Nevertheless, this life is all the atheist has to hold on to. So, like the man dying of emphysema who keeps sucking on his cigarettes, the intellectual elites embrace their Darwinian world-view in hopes that somehow, against all indications, they'll be able to squeeze out of it a few precious drops of meaning for their lives. They're hooked and can't give it up.