Answer: the Nazi infiltrated Austria long before 1938. Moreover, Austria was and is German-speaking country which made things much easier. The only challenge was predominant Catholicism of the country and its close relation to Mussolini´s Italy ...Germany´s occupation of Austria could create some friction with fascist Italy. Situation in Czechoslovakia was quite ...Hitler was able to seduce 3 millions of German speaking Czechs but not the rest of the population. Moreover Czechoslovakia had its own military industry. Czechoslovakia was defeated not on warfield but on diplomatic field (the French and the British abandonned their Czech allies). In other words Czech politicians betrayed Czech army and population (the same was repeated in Prague Spring, 1968).
Explanation: So-called Anschluss took place more or less 6 months before Munich Crisis (Munich negotiations of Hitler with Mussolini, Daladier, Chamberlain...October 1938) about handing in of Sudetenland in favour of Germany. In spite of this submission, Germany invaded Bohemia and Moravia already in March 1939.