With respect to German Jews your point about who managed to get out is partially true, but only partially. The emigration of German Jews can be roughly divided into several phases. The first came immediately after the Nazis came to power. Then the numbers fell dramatically but slowly rose until the Anschluss and especially Kristallnacht when suddenly almost every German and Austrian Jew wanted to leave, with the exception of the elderly. In that first phase it was precisely the politically and socially active who were most likely to emigrate - those who weren't caught up in the sweeps of Communists and SD's or who were released from the concentration camps soon afterward. Until the final flood, finding a place to go wasn't that hard. It was only in the final phase that the wealthy and/or connected had a real advantage.

In the case of the Jews of Poland and the Soviet Union - the large majority of the victims of the Shoah - you  are more wrong than right. Wealth was no advantage. On the other hand being a communist activist was since you were likely to flee along with the Soviet authorities in 1941. As a result communist activists survived in very disproportionate numbers. You are right for Poland  in two ways - the assimilated Jews (roughly ten percent of the Jewish population) were more likely to have friends who could hide them or their children, and they were also able to 'pass' as Aryans.  Better off Jews, along with non-communist activists of any political stripe were also more likely to end up in the Gulag where as it turned out their chances of survival were higher than in German occupied Poland. Assimilated Jews tended to be middle class, but considering that some three quarters of the Polish Shoah survivors survived in the USSR, and the vast majority of assimilated Jews in occupied Poland died, the net effect favored left wing activists. (some 200,000-250,000 survived in the USSR vs 60,000-80,000 in Poland)