With aid from two major countries and millions of elites, why was it destroyed by one country in just 15 days?

With the aid of two major countries, the country that perished in less than 15 days was Poland.

At that time, Poland said that it had 800,000 troops. The Polish army had always been based on horseback combat, while Germany, which was opposed by it, had the most highly equipped armed forces in Europe at that time. Compared with him, Poland seemed too weak. Moreover, the aircraft, artillery shells, and tanks that Poland claims to the outside world are all temporarily prepared. Six hundred Polish planes sounds like a lot, but it's actually of no use. Many aircraft have not been repaired for too long and are very dilapidated. They are of little help in a war. Moreover, once the war started, Poland did not have a general who could control the overall situation. The performance of Poland's 800,000 cavalry was also unsatisfactory. There is no unified command and no tacit cooperation. The German army has 1.5 million. When the war actually breaks out, Poland will be able to resist half of Germany's troops, which is already very good. Although it was the first time for Germany to lead troops into a war, there were many flaws and deficiencies in commanding the army. If Poland could calm down and attack Germany's flaws at this time, it might still have a chance of winning. But the cooperation between Poland is not good at all.

Although Britain and France said they would help Poland, it was actually time for Poland to go to war. Britain and France just watched Poland being beaten by Germany and remained indifferent.

Poland once said: "We will lose our freedom if we get close to Germany, and we will lose our soul if we get close to the Soviet Union." ?Now, Britain and France no longer regard Poland as their brothers. And the Soviet Union is not a good person either. To sign an agreement with Germany to carve up Poland, the Soviet Union's idea was that Germany would not enter its own territory so quickly across Poland and regard Poland as a buffer. Every country has its own wishful thinking. Therefore, what Britain and France said about supporting Poland was just casual talk. As for the United States, it had already taken away Americans in these countries and would not participate in this war.