There's even a Torah Im Derech Eretz society and website :)
None of it is large scale in terms of numbers of people. But it's still out there, with passionate members.
So what happened? Well persecution in Germany pushed millions of Jews to Eastern Europe where many of the distinct practices and outlooks of German Jewry were lost. I'm going back 500 years here. That was probably the biggest factor of change.
Then came emancipation and assimilation in German during the 19th and 20th centuries. That drove most of the remaining people away.
Then came the Holocaust.
Post Holocaust there wasn't much left and it was easy for Germany Jewry to get swallowed up by Eastern European Jewish culture, due to the sheer numbers of Eastern Europeans,and particularly also since German Jewry had been transplanted to new lands without its institutions.
We could analyze further perhaps and say that Israel, one of the new lands for German Jews, was busy just trying to survive and also, it's not in a Western/Germanic part of the world. There was a swallowing there of sorts by Sephardic Jewry.
Photo of a car on a curb in B'nei Brak - not something you'd see in a Germanic country.
As for America, well any readers of this blog know that I often characterize America as a largely Germanic country. So German Jewry might have thrived there. And what did happen is complicated. German Jewry in its pure form became restricted to the few places I listed. But German Jews contributed mightily to the reconstruction of Torah observance, via the Agudah, whose founding and building was done largely by German Jews, via publishing outfits like Feldheim, and through all sorts of community work in kashrus, mikva building and other projects that tend to be done well by well organized sorts of people.
Many kids from Washington Heights went to Lakewood and other Eastern European style yeshivos and shed much of their German Jewish practice and outlook. I'm not judging whether this is good or bad. Just reporting what happened.
I'd love to see a truly scholarly analysis on all the events. There are a number of terrific books on German Jewish history. Mordechai Breuer and Haym Soloveitchik are two of the more prominent Torah observant authors; although much of their history, particularly that of Dr. Soloveitchik go back a few or more centuries. Marc Shapiro has written a number of articles on more recent history. The book Frankfurt on the Hudson is a real gem for a study of Washington Heights and the German community.
Then there's George Frankel who grew up in KAJ WH and wrote a few essays on the changes there.
Whatever the analysis, here we are. German Orthodoxy is not taking over the world but it is still a real option and Jews of German extraction are all over the Jewish world. And then there are the Jews like me whose ancestors come from Eastern Europe but who grew up in a Germanic country and gravitate to German Orthodoxy. German Orthodoxy is very real in people like that too. I can assure you.