The Holocaust was a decision taken by one of the two pillars of the EU, Germany, so countries nowadays being rich or poor has nothing to do with past “good” decisions of those countries populaces. And before anyone commenting that the Holocaust and the German economy are two orthogonal subjects, just look at the corporate history of German industry giants VW and Bayer.
Neither VW and Bayer are rich because of the Holocaust. They are rich because of good business environment and good corporate decisions after 2nd world war.
From a purely economic viewpoint Holocaust and 2nd world war were very very stupid decisions.
Worse, Germany has one of the worst upward mobility stats in the EU. If you look at the filthy rich families in Germany, most of them have ties to benefitting heavily from WW2.