What were the real factors that led to the discreditation of Appeasement as a policy for foreign diplomacy?

Appeasement was one of the most important causes of WWII. Today people say that it was Chamberlain's appeasement that started the war. It is true to some extent because Chamberlain couldn't prevent the war. However, Chamberlain had actually began thinking to change his policy after the Munich agreement; he was forced to change his appeasement policy because many events happened in 1938-1939. Let's see how the events affected Chamberlain's Policy: Events in Europe pressured Chamberlain …

…a war. Chamberlain also felt appeasement policy was no longer supported any more even by Conservative Party by seeing the resignation of First Lord of the Admiralty and votes against his supporter Hogg. Furthermore he was preparing for the war from the end of 1938. So, Chamberlain had to change his policy because of the environmental factor that gave him more and more pressure and consequently made him noticed that appeasement was not useful at all.