It has been said, by an author whose works are rather famous and prolific in number of sales, that fear is the mind-killer. That, while undoubtedly true, also seems to suggest that fear is really the only mind-killer, when in reality, there are multiple mind-killers of varying degrees of efficacy and chronology. Boredom, for instance, is a mind-killer. Stress is a mind-killer. Anxiety is a mind-killer. And this doesn't even get into the less metaphysical realm; smoking, for instance, is a mind-killer.
What this is to suggest, ultimately, is that the world is full of things that can damage one's thought process, ability to reason, and feelings of comfort. That we have so adamantly worked to alleviate these problems over time, with little to no success, explains much about people's desire for means of escapism.