Why do you think socialism never found widespread support in the united states?

Fear of communism, the American tradition of self-reliance, political opposition from the wealth/business interests.

Taking care of poor/vulnerable people, reign in abuses of big business and private wealth.

High tax burdens if programs become too generous, a risk that people would lose incentive to work hard

One reason why socialism did not take root in America is because of the culture. The American value system and the American concept of the nation are egalitarian. The American Revolution was essentially a rebellion against as strong states. Socialism is largely about big government hence its failure in the United States