I assume that you are talking about the time in 1830s and 1840s when there were a number of attempts at building utopian communities. I would argue that the utopian communities failed because A) utopia on earth is impossible and B) the systems they were trying were too radical.
Take, for example, the Shakers. This was a community that tried to do away with the selfishness that is so harmful to human life. They wanted to have all their property in common and they wanted to avoid any sort of intimacy between the sexes. They thought that romance and marriage led to selfishness because those things made people belong to one another (as a family) rather than to the society as a whole.
This was very radical -- a place where there would be no marriage, no sex, no private property. No wonder it failed -- people don't tend to go in for things that are that "out there."