Well, I would venture to say that there are many inter-related factors, but basically, it boils down to one… MONEY!
– Hungarian Jews were much wealthier than their European counterparts. They had the means to do things more b’kovodik, and that was passed onto their offspring. Affluence makes it easier to do things more respectably.
– Hungarians always followed the derech of being ehrliche baalei batim, as opposed to cobblers and poor yeshiva students. This derech comes from the Chasam Sofer, who was the rov in Pressburg (then part of the Austro-Hungarian Empire).
– Additionally, the Yidden in Hungary were not as prosecuted by the goyim as in other regions of the continent. This allowed them to work and maintain their money better than others in Poland, Lita, etc.
– Hungary was one of the last countries to be affected by the Holocaust. Their collective psychological suffering wasn’t as lengthy as it was for others, which means that they were able to rebound more easily than Jews of other nations. (Of course, I don’t want to minimize anyone’s terrible suffering, and this is just my theory.)
– Hungarians were exposed to a culture of luxury because the Austro-Hungarian Empire was wealthier than other countries (Poland, Lithuania, Russia, etc). Again, being exposed to that wealth got transmitted into their genes, and B”H the descendants of Hungarian Jews have channeled that culture of luxury into beautiful Yiddishe traditions, enabling the rest of gang to learn from our wonderful ways and embrace beauty.