Why has Europe been dependent on U.S. military support since World War II?

After World War II, Europe had essentially destroyed itself and required American support to prevent it from becoming communist-dominated. The United States became the primary bankroller of European security, creating a dependency relationship where Europe relied on American taxpayer dollars to defend itself against the Soviet Union. Even after the Soviet Union collapsed, Europe failed to develop self-sufficiency in defense. Instead of building its own security capabilities, Europe continued to depend on American resources and protection. This nearly century-long reliance has created a situation where European nations have not taken responsibility for their own defense needs, prompting calls for Europe to finally 'stand up on its own two feet.'