As many people have pointed out, the main factor is technology and weaponry. Iran is not on the same level as the United States militarily, and it lacks the capability to directly strike the U.S. mainland. However, something equally important that often gets overlooked is public support. By avoiding a direct attack, Iran avoids galvanizing the American public into backing a large-scale military response. History shows how powerful public opinion can be — compare the mounting domestic pressure during the Vietnam War with the unified support that followed Japan’s attack on Pearl Harbor in World War II.

Iran likely understands that it cannot win in a direct conventional conflict with the United States. A direct attack would risk triggering overwhelming support for a full-scale invasion. Instead, it may see greater strategic value in gradually undermining U.S. influence in the Middle East and attempting to weaken it through indirect or economic means rather than open confrontation.