Curiosity, you’re wrong. All the younger Gedolim, who were NOT born in Europe also speak Yiddish. As do their children. And all the great Litvish Yeshivos in EY teach in Yiddish. (I don’t have to mention the Chasidish.)
Also, the Ashkenaz / Sephard worldwide demographic breakdown is about 80% Ashkenaz / 20% Sephardic. In Israel it is only slightly less and you can check this with the Israeli Buerea of Statistics. Outside Israel it is even a much larger proportion of Ashkenaz. Before WWII it was even much greater difference. In 1931, 92% of Jews were Ashkenazic.