Question: "Hey Eliot, what's so wrong with the modern world?"
Eliot's answer: "Everyone is way too selfish."
Question: "So what?"
Eliot's answer: "Well, haven't you ever wondered why you're so lonely? That's why."
In "The Waste Land," the great despair of modern existence doesn't just come from a sense of meaninglessness, but from a very deep loneliness. This loneliness, in turn, is something Eliot thinks we create for ourselves by constantly pursuing our own selfish interests. It's pretty simple: you can't spend your whole life trying to beat the people around you, then turn around and complain about being lonely. Modern existence, with its emphasis on individualism, is a breeding ground for isolation and loneliness, and the major problem with modern people is that they don't seem to realize that they're responsible for the isolation that's always eating at their souls.
In "The Waste Land," Eliot suggests that spending a few hours in the soup kitchen every week will make all of our bad feelings go away.
According to the final sections of "The Waste Land," it's impossible to reach spiritual enlightenment and still think of yourself as an individual.