If Italy could be relied upon, Germany would have unified the world long ago. What does this sentence mean?

During World War II, Italy and Germany were allies. Italy during World War II should be one of the more funny countries. Their great dictator Mussolini was a standard scoundrel. Italy was the first regime to establish fascism, so it always considers itself the boss. Once, Mussolini said in a letter to Hitler: "No one knows more than me, because I have more than 40 years of political experience." The implication is that I am playing politics. At that time, you were still begging for food in Vienna with a porcelain basin!

Although Mussolini boasted loudly, he began to be cunning when encountering specific problems. At the beginning of World War II, Hitler eagerly hoped that Italy would come out to help. Because according to the "Steel Treaty" signed by Germany and Italy: "Once one party is involved in a war, the other party will automatically join the war." This is a very "manly" agreement. However, Mussolini refused to admit it. His reason is: "Italy will not be ready until 1942, but it cannot be done now. Because our country is short of food, wood, and steel... (anyway, everything is short). If there is a war, the British Navy will blockade the Mediterranean Sea. We're screwed. "So, military assistance is not possible, but we will support you morally.

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And Italy was the first to surrender. In short, he is a relatively unreliable guy