“They bind our hands and then complain that we do not make use of them.” –Moses Mendelssohn
In 1933, German Jews were looking not forward, but backwards on their own history. Between 1790 and 1933, German anti-Semitism was constantly growing, and then subsiding; institutional anti-Semitism presented a consistent barrier to Jewish achievement and advancement, yet, they managed to successfully push against it in their quest to create a place of their own in German society. For a wave of anti-Semitism to not only stick around, but to grow more dangerous over time was unforeseen. It had no precedent in the history of German Jewry.
Using history as their guide, German Jewry had no reason flee Germany in 1933. They had no reason to flee in 1935; past waves had lasted more than two years. They only realized that this was something new in 1938.
In the five years between the boycott on Jewish businesses and Kristallnacht, the events of 1780-1933 came together with Nazi legislation and propaganda, non-Jewish attitudes, and global immigration law to form a situation which many German Jews could not, or would not, recognize as lethal until it was too late.